The ps/2 mouse driver is now extremely stable!

Gnome and KDE are in the ports tree and kept very up to date. Everything there basically works. Most supported hardware just works out of the box with very little tinkering.

Of course there is less hardware supported than Linux and support can lag a bit, since there are few people writing drivers. But modern Thinkpads work quite well.

All that said, I have found Gnome to feel a little slow on OpenBSD compared to running on on the same hardware on Linux. So on OpenBSD I mostly use dwm, which feels super fast.

Generally most everything you want can be found in the ports tree.

That depends on what you do to be honest. Web, email, programming, spreedsheets, wordprocessing have been fine for over a decade. Heavy 3D stuff, not my first, second or third choice.