I have just received a sample of Boba U4T (the non silent version of the U4), these are amazing.
Zero leaf / spring noise, I’m pretty sure the spring is lubed, but the switch itself is bone dry, yet still smooth with no binding.
Very minimal wobble, very close to my BOX pinks, and the housing is very tight, no play.
The tactility itself is very snappy, it’s a P profile, but a rounder and longer than the T1 for example..
I’m not a tactile person so I’ve only got a T1 sample (and MX brown) to compare.
The U4T is a fantastic switch, putting aside the tactility, it feels very high quality, honestly puts the T1 to shame, with its high leaf/spring noise and loose clicking housing.
Only downside (to my taste) is the sound, the U4T tries to mimic the Holy Panda thock(?) with a long stem, I prefer the sound of the T1 but I’d still get the U4T, not sure how it’s not popular with its (relatively) affordable price.
Ended up a bit long like a review, hope it helps you.