I have heard good things about SnapStream.
SageTV is another one that seems to have a lot of faithful users.
You will find that PVR software is kind of like Windows vs Linux. There is a big battle over which is the best and the one you like is the greatest thing since the wheel.
Snapstream (or Beyond TV I believe it is called now) used to be better than Sage TV, but with Sage TV 2.0, things have changed. I suggest you download the trial of both software packages and decide for yourself, as everyone has different requirements.
One other thing to consider.. your capture card. Sage only supports hardware encoders like the PVR-250/350. BeyondTV, however, has support for many other cards including the AIW series. This alone may make the decision for you.
I have been a BTV user since back in the day (v2.0) and am very impressed. But as Electron said, "Snapstream (or Beyond TV I believe it is called now) used to be better than Sage TV, but with Sage TV 2.0, things have changed. "
The one thing that I like about BTV is the community. With the new 3.5 version soon to be released, many more good things are to come...they are opening an API for user plug-ins, along with dual-tuner support, and some other good tidbits.
I also, second the motion, that you try both. By the time those trials run out, Meedio's PVR solution will hopefully be out, so then you can try that one. If you want o try a Free window's based program, look into GB-PVR. Its still in its infancy, but hey, its Free and coming along nicely.
I personally am using BeyondTV (running beta 3.5), and I also like the community. Very much like the HS community.
For awhile I was using the SSGirder plugin to get the channel change info to girder, which in turn passed it to Homeseer (actually was fairly quick) and HS would send the IR stuff through my ocelot. I was finally able to get my cable co to enable the serial port on my cable box, so am doing it directly now, but I still use girder to update Homeseer with channel changes.