I have been using MythTV for 4 1/2 years, it has been our main method of watching TV for most of that time. My main backend is a Pentium D 2.8GHz machine with 1.5TB of local recording space, and two PVR-150 cards recording off of analog cable. I also have 2 dual tuner HDHR's hooked up to a CM4228 antenna, and an HD-PVR connected to a Rogers HD terminal. I have 1 TB of NAS space for various and sundry (music, pictures, DVD rips, etc). My main frontend is a Zotac ION based machine, the secondary frontend is in the process of being built from an older laptop. I also have it installed on all the regular laptops on the house, just in case. All machines run SVN trunk builds that are usually within a week of current. We are extremely happy with the setup, and wouldn't trade it for anything.