I watched a couple and so far, in the rank of 1-10, around 7-8. The fact it's not 100% compatible is mentioned, especially with homebrews (and I think more so on the 7800 front). Controllers get the thumbs up and other controllers, like trackballs, seem to work fine.
I should be getting my joystick and paddles on Monday. I'll give them a try later in the week and I'll let ya know!