I'm on my third 6S+, and not for OCD reasons either.

The first had a faulty home button and the second had a dodgy screen but other than that they were spot-on. Well I'm experiencing the dreaded unlock lag and random screen freezing on this new one. The battery life is terrible too. I would say that if anyone has consistent lag or freezing on their 6S+ then it's a hardware fault because I've seen enough of them now to know that it shouldn't exist. Two out of three phones haven't exhibited this issue.
For the record it's the install of 9.0.2 the phone came with and I haven't loaded a backup. Touch ID is off, spotlight is off, reduce motion is on, all system location services are off, I'm using a static photo as a screensaver and background refresh is off. I'll try a clean install of 9.1 before I exchange it but there's no way I'm accepting 6 Plus-style lag and freezing. Damn Apple's QC! The screen is fine on this one but I seem to be swapping one problem for another all the time.