Have you ever actually used anything besides the ComCast PVR? If not, don't waste your time on the "cheap" alternatives: you'll hate them. Your $15/month pays for convenience, integration, one-touch program grid, and ability to record two or three shows in Hi Def on different channels at the same time. Nothing else works like this except TiVO or Moxi, neither of which are worth the money unless you are hell-bent on networking them to your computer to rework the recordings and make DVDs or iPhone/iPad files. The CableCard requirement is a pain and prone to not work right, ComCast is notorious for repeatedly screwing up installation. Plus, it would take six years of the ComCast PVR fee to pay off a TiVO with lump-sum lifetime subscription.
There's no free lunch. The only cheap no-fee recorder is the Magnavox at $199-249. It has no program guide, can't accept a CableCard to integrate smoothly with your cable service, can't record in HD, timer must be manually set like an old VCR, can only record one channel at a time, and if you want anything beyond the dozen basic channels on ComCast you'll need their decoder box anyway which means you have to set that to the right time/channel as well. Doesn't sound like such a bargain anymore, does it? If all you do is watch and erase, and you have no interest in making DVDs or iPad files, there's no real payoff for you in switching to a generic recorder. Stick with the ComCast PVR and avoid disappointment. We can complain until we're blue in the face, but cable/satellite in 2011 is a totally closed system: in for a penny, in for a pound.