While I've seen issues with it posted around I figured I'd give it a try.
I don't even have it yet and my mythbox is currently unusable.
I upgraded the kernel from 2.6.18 to 2.6.25 in preparation, wanting to get the latest DVB stuff so it'll work when it gets here. (it'd been sitting at the old one cause something broke for my hpt366 back in 2.6.8 and i found a patch someone had made, upgraded to the latest at the time then left it alone)
Now my existing bttv card is giving choppy audio and nothing but green video.
From what I've been able to gather the kernel changed something in the v4l system and myth doesn't like it. TVTime runs just fine, but mythtv fails it.
I'm currently recompiling mythtv to see if it just needed to be compiled against the new kernel, but if that doesn't work I'll have to downgrade to 2.6.24 which is reported to not have this problem.
There are a few other things to try according to the mailing lists, but switching from nvidia to nv xorg driver didn't help (didn't think it would, it's failing on both the front end and back end, but it worked 7 hours ago.
The one person in irc.freenode.net / #mythtv-users that started trying to help turned into an ass quickly and stopped helping. That's the 2nd or 3rd time that's happened there. (seriously, I just asked if his proposed problem re:video display issues would be different because I was running separate back end and front end. He said no and to test an a 'known good' machine. I said the front end was known good cause I haven't done anything to it in all this time. He said "You're the boss" and "* support session ended." Even later when I told him I'd played a recording from before the upgrade just fine but one after failed miserably, and also afer i pointed out the mythtv mailing list stuff about the kernel, he hasn't said a damn thing.)
ETA: through some ebuild editing I applied the patch referenced here:
http://svn.mythtv.org/trac/ticket/5608 and am recompiling myth again. I'mma play some quake2 while that's going
ETA2: The patch worked! I have TV back!