So far, I think I like the SmartTrack better. It seems to retain some tightness throughout the week instead of losing the tightness after a few days like the older material. Also, although I only have a total of 4 trays as a gauge (two sets of top and bottom), so far it seems like there's less edging issues. I'm not sure the best way to describe it, but with the old material, it seemed nearly every tray had a little sharp piece where the material wasn't cut quite evenly, so I'd have to file it down. I haven't noticed that with these trays, at least not yet.
I will say the only issue I have now is that the left side of both trays isn't staying over the back molars. I find it interesting, however, that they only cover half the tooth. With my initial trays, they covered the back molar completely except for the left bottom. With these refinements, they're all half-covered except the bottom right. I'm hoping that means those back molars don't need to move, so I'm not stressing out too much over the fact that two of them don't sit right. But I'm using my chewie pretty well each time I put my trays back in after eating, so I hope that helps these refinements track better. I never knew about chewies until the Invisalign board, and wish I had known about them before I started. Maybe I wouldn't have had such tracking issues in the front if I used them the whole time.
I had my 6-month dental checkup last Tuesday. Unfortunately, I had a lot of plaque and gingivitis, but thankfully no cavities. After I left, I realized that maybe it was because I was using the same trays for so long (bottom for months, top for at least one month) and I had a hard time cleaning them since they got gunk on them. Even when using Retainer Brite and brushing them, it was still a problem (it's unfortunate that my Sonic Cleaner died... I haven't gotten a new one because I'm afraid it will do the same thing). This is part of why I'm glad I change weekly - less risk of gunk build-up! I also decided to get really proactive with cleaning. I've been better than pre-Invisalign, but I feel I need to do more to have the healthiest mouth possible.
Well, that's all for now!