While many people say that it will take a great deal of testing, you might disagree if you look here:
Of course, this is with KnoppMyth, not if you want to install Linux and everything yourself manually.
http://www.bitbenderforums.com/~ralpha6/knoppmyth/knoppmythtv.htmI am wondering if anyone has tried using a PVR500 with MythTV and/or Fedora Core 3 and if so, how well it worked. We want to possibly run dual PVR500s so we can have 4 inputs. Is this possible in this way?
Well to be fair you are posting in a thread that is over a month old and the driver has been improving and the knoppmyth alpha/intermediate releases have been adding better and better support making it easier and easier (and that guide you link to is of great help as well!

)
I'd currently characterize the linux/mythtv ivtv drivers for pvr150/500 as pretty solid, but it may take some doing to get configured/working depending on platform (although it looked like you made short work of it!)
It just keeps impvroving! I'm going to add your guide/walkthrough to the Linux resource sticky and to the project example page

rampy