I've owned vinyl smart dolls in the past and currently I only own a cortex hybrid. I wanted to offer my opinions and some info on this material that I really was not able to find when deciding to get it or not. As you'll see, I wanted a lot of info. I own the tea tone, which is not light and not dark either, so some of these things may effect other tones more or less. I'm someone who bought the doll for sewing purposes and I'm quite happy with it. That said, I want to put out some info about my experience and thoughts.

I'm also not a very careful or cautious doll owner. I like to handle my dolls a lot, I like to dress them and display them, and I pop the limbs and head on and off all the time, I change the eyes, I do all that scary stuff and I've had absolutely no issue, even with cortex. I won't be addressing seam lines. They don't bother me. If they bother you, you're valid too.

Material:

The material used for cortex is called Asaflex supposedly, although I have had limited success finding more information on the material beyond the listing for it on the Asahi Kasei wesbite, which shows the material's structure at 2.5 microns being sort of bubbly and round. I bring this up because it's important to note that if you want to work with this material the way you would work with say, gundam plastic (typically ABS) you may need to take into account the potentially different structure of these two plastics. ABS is just a long chain, this doesn't look like it is. I'm not a material scientist though. I am not 100% confident you could heat up a tool and slide this plastic back into place the way you can with ABS, so I cannot recommend doing repairs that way or trying to remove seam lines with the same kinds of fusing glue. If I ever get brave about it though I'll include the results here.

Scuffing:

Scuffing on tea isn't terrible, but it's not completely invisible, and MAN is this stuff easy to scuff.

It's also worth noting that the sand paper which came with my doll is FAR too rough for use in my opinion. When I tried using it, it just looked like I had rubbed even more scuffing onto the doll. This disheartened me, but later I found out that dry magic eraser works far better as a sandpaper. It's much more fine, and after rubbing the arms of my doll down with it, the plastic texture was almost indistinguishable from the vinyl. It can also get some smaller scuffs out. Limited success on the tummy scuffs though. However this matte texture fades eventually and treatment seems like it's just something that's a part of the maintenance with this doll.

Since I tend to dress my dolls in clothing that covers most skin, scuffing isn't actually a big deal. My doll stays kneeling on my desk most of the time, so instead of buying the vinyl knee pads I just made some protective knee socks instead. The knees did scuff a little, but not a whole lot.

Staining:

I've stained the vinyl bust and managed to get it out with magic eraser. The same outfit had this problem all the way down, but there was not a single stain on the cortex material so I believe it was a decent test. Now, I'm not saying it's not going to stain, but after dealing with milk vinyl it is kind of refreshing to be able to leave it and forget it.

As for removing stains in cortex, I will report what I find here when that happens. I'm a little skeptical of Danny's insistence that paint thinner gets stains out of these dolls (but I'm skeptical of everything) so when the time comes I'll be eager to see if it's true. Because, that would be really easy.

Yellowing:

I have not yet owned the doll long enough to see if yellowing is going to be an issue, and this is also something I'll be keeping track of. I know it doesn't show up nearly as bad as tea anyway.

Fingerprinting:

Since the outer material is matte, it's not a huge fingerprint magnet either. Obviously I still wash my hands before handling my doll for an extended amount of time, but it's not the biggest deal. I'm pretty sure even pizza grease would just wipe right off. 😆

It's also unclear what happens to this material over time with exposure to the oil in human skin, but since Asaflex has several medical applications, I'm somewhat confident that it's immune to any ill effects.

Chipping:

I mention this just in case anyone's curious. Asaflex is a harder material than vinyl for sure, but it's softer than resin. Chipping has not been an issue for me at all, and I don't ever see it being an issue unless I drop the doll, which even then it's extremely sturdy. Another plus.

6//2/2020 EDIT: This is no longer true. Cracks formed beneath the main panel in the back of the upper arms on both sides. It appears the stress is just too high in that area. The cracks are small and I didn't even notice them until someone mentioned that it could be an issue and I looked for them, but be aware that some parts of this doll may experience stress and subsequently crack.

Frame strength:

I don't know how much cortex weighs when compared to vinyl because I don't have a vinyl girl (at the moment 😉 ), but something that concerned me was losing frame strength faster because of the weight. I'm confident though that nothing's actually effecting it, because this girl has been propping up an iPhone 11 for a few weeks and had no issue.

Cortex busts:

If I had one main gripe about this doll other than the scuffing, it is the cortex bust. It is truly bizarre. Aside from limiting mobility bending forwards and backwards, it also cuts off some mobility in the arms when trying to push them closer to the torso to get those really girly poses. The cortex bust also comes with two little rubber O rings that pad the head from the bust, so there's not as much of the peg connecting the head. I'll lose those eventually but oh well.

My problem is with removing it and getting it back on. This cortex body came fully assembled and glue together, so the plastic bits that Danny recommends nipping were already nipped. Two things make this bust a nightmare to get on and off: the central support, and the tabs in the arm sockets. The central support requires that you keep the spine at a specific angle to get it on and off, like seriously make sure that thing is straight. However, even when you do get the bust back on, there's these tiny little tabs around the arm ports which make it extremely difficult to get that central hub piece that connects the spine to the arms actually in the right place. This means there's a bigger gap between the hub and the opening, and this puts pressure on the arms when they're connected. There's been times I thought I had it in only to find a few minutes later that one of my girl's arms had popped out! It's extremely frustrating and doesn't actually keep the hub piece secure. To this day I have yet to get the cortex bust on in a way where the hub piece sat properly in the tabs on both sides of the bust. My instinct is to cut these little tabs out with some gundam nippers, but I'm not brave enough to do that yet. I wish this thing came completely hallow, but here we are.

Any advice on how to do this smoothly is extremely appreciated.

Mobility:

Decent, especially once the bust has been replaced with a vinyl one. The leg openings are a little different on cortex so they can sit decently. I have noticed the arms can't quite touch the shoulders the way vinyl ones can. You get maybe? 15~20° when you try to do that. Otherwise, as expected.

Verdict:

Obviously I only speak for myself, my experiences, and what I wanted when I bought this doll. Danny was really good about setting expectations with this, so overall I actually am really happy about my purchase and I think it was the right choice for me. It took me some time but I've definitely warmed up to it a lot more over the time I've had this doll. So much so that it will be hard for me to choose between vinyl and cortex for my next doll... I think both materials are fantastic. Since I'm lazy I do like how you can just set cortex and forget it. It lets me enjoy the doll to the fullest without worrying about staining and whatnot because I am a very casual doll owner. So if you're looking for advice on what to buy ... Both! 😄

6/2/2020 EDIT: Because cortex is most likely going to be discontinued, I can no longer recommend getting a cortex doll. The doll had a lot of potential but I'm afraid I'll have to leave it at that. I no longer own a smart doll in vinyl or cortex and will be avoiding the company until the ability to get replacement parts for a doll no longer hinges on personal standing with the founder of the company. My best wishes to Danny and the team at smart doll for their future endeavors.