I've seen a couple of threads on this brace but thought I'd give my feedback after buying one and owning 2 SBA3's and an SB SOB brace.
Long story short, for a sort of 300BO PDW build, I decided to go with a LWRC UCIW buffer tube for a shorter OAL.
I've seen some chop their braces to allow them to fully collapse on the shorter UCIW tube, but I noticed looking at pictures of the T5 brace that it appeared to have right about 1" of unused buffer space and might not need to be chopped, or if so, very slightly. So I picked one up.
I don't have the UCIW tube quite yet, but having my hands on it, I've got to say I'm impressed. I like how the brace section is reinforced with blackened stainless springs and the closure area where they meet at the bottom has dowels that keep things in place. I also like how the brace section isn't molded into the body, but is sandwiched with through bolts and polymer on the outside, pretty slick.
And the buffer tube that it comes with is one of the nicer finished tubes I've gotten. Fit between the tube and the brace is about the same as the SBA3. Hopefully I'll get my hands on a UCIW tube soon and see how it fits, and post back with pictures.
Fully collapsed position and extra space on standard carbine tube. At the worst I might have to trim the slight flare at the beginning:
Dowels and reinforced brace portion (the flat blackened stainless springs):
You can see the sandwiched setup of the buffer area between the body and polymer pieces on the outside:
Pics of the included milspec diameter buffer tube, nice anodization, not sure if 7075: