I have been using BIAB instead of "traditional" hard gel since October 2017. I was finding that after 2 or 3 infills the hard gel was becoming quite brittle and despite careful prep and application, there was usually some Lifting. Removing hard gel is a real pain and I hadn't been overly impressed with the soakable hard gel I tried. I had been reading all about how wonderful BIAB was for some time so I decided to give it a try, although I was a bit concerned that they no longer sold a specific lamp to cure it.
I tried it out on myself and my friends, family and regular clients that were up for it and we were all really, really impressed!
The consistency is more like a very thick gel polish than traditional hard gel so it's worth flash curing 1 or 2 nails at a time to stop it sliding into the sidewalls, but you soon get used to it. I love using the various nude shades as they make a lovely base for colours (they don't detract from any of the colours either) and they can be used on their own, but the really good part is when you're infilling you can clearly see when you have removed the gel polish, which isn't so easy with a clear product.
BIAB is a dream to file yet it is so strong and it doesn't get brittle with age and Lifting is very rare, so long as your prep is good. It lasts so well and the majority of my clients only come back because of regrowth, bit because they've chipped or lifted. The other good point is that it can be soaked off in acetone, although I rarely need to do this as you can just infill over and over again as long as you debulk and rebalance.
I use it as an overlay over natural nails to give extra strength and also over tips for extensions. You can also sculpt with it. TGB say it's good for medium length extensions. I think if you want to do stiletto style tips or really long their Gel Pot would be more suitable.
TGB brought out their own lamp a few months ago. It has a very useful setting that cures slowly to start with which really helps to eliminate the heat spike that is common with BIAB.
I think it does live up to all the hype!