Well, I use the mainline since I would like to start contributing sometime later. Also, I have a custom bootloader set up that managed to integrate nicely with Secure Boot, VMWare modules have to be recompiled with almost every kernel update since it breaks the Virtual device monitor and I had to write a script to automate that patching process.

Video tearing has been a constant problem if you use any type of compositer like Compton or the one that comes with XFCE or GNOME. I tried it on various systems and the tearing is there. A lot of people don't seem to mind though. For some reason, the Ubuntu maintainers don't think my hardware (or rather all laptops) should have the capability to hibernate to disk so they disable the /sys/disk (Im not sure I got the correct filename) which enables suspend to disk (this is one of the reasons why I need to use mainline anyway). PulseAudio doesn't play nice with DACs, ALSA is a pain to set up.

I really like Linux (so much that I keep 'ricing' my system) but these are the kinds of things that I'd rather not spend my time on.