They work a lot better with FTTP, very rarely restart, etc.
No they don't, maybe they have gotten better over the last few years, or maybe I was just unlucky and the several I had were all faulty, but I have had nothing but issues with all my Smart Hubs including their Smart Hub 2 which I have been given over the years I have been with BT on FTTP.
I was getting loads of reboots all the time (especially when we were using our connection fully), especially when we were on BT's top tier package, so lower tier packages might be fine.
Also the Web UI of all the smart hubs that I have had have all been sluggish when we we were using our connection.
Loads of UI issues and no place to report them, I used to report them over the phone and via Twitter DM's, was told it would be passed on, but was never fixed.
Moved over from BT's hardware to my own 3rd party router MikroTik RB4011iGS+RM and all those issues were gone and I only lost connection for a few seconds when the Public IP changed.
Paul