I have been using MediaPortal for over a year and am blown away by it's features and the price can't be beat (Free). They have 5 to 10 SVN updates a week so the support is unmatched. They have one of the most active user forums as well. I have tried most of the other PVR programs available including MS MCE and they have all fallen short in my opinion. It has been tested with 7 TV cards with minimal impact on the CPU load.
To check this test out click here.The latest incarnation just released is MediaPortal TVServer with some pretty impressive features.
# Separation between front-end and back-ends
# Supports multiple clients
# Supports multiple tv-servers
# real-time streaming of radio/tv to clients
# Supports analog h/w cards
# Supports DVB-C / DVB-T / DVB-S / ATSC (BDA drivers)
# Supports Skystar 2
# Supports CI/CAM interface for FireDtv/FloppyDtv/Twinhan and TechnoTrend
# Multi-tuner support
# xml tv import of EPG data
# Grabbing EPG data directly from the DVB streams
# Recording/timeshifting/placeshifting
# Recording to real .mpg mpeg-2 format
# Teletext
# Plugins
To view the info on the MediaPortal TVServer click here.To find our more info on MediaPortal click here.Just my 2 cents,