I am now the proud owner of a Tivo HD. It was "easy" to set up, which is to say that the TiVo itself was a cinch. The only issues I had were with signal quality - the picture on the TiVo looked terrible compared to the TV itself. I tried changing the aspect ration, the video output settings, and so. I finally settled on signal strength.
To test whether the problem was TiVo's signal processing or something else, I replaced the cable into the back of the TiVo. Our cable is split 4 ways - TV, Internet, Wireless TV for the Kitchen, and TiVo (formerly the media PC). That requires 3 splitters, each chained to the next. To up the signal strength, I cut the chain early, and ran the cable directly into the TiVo. Problem solved. Indeed, I had to go back and set the video output settings higher to let the TV really shine.
From unboxing to completion - 1 hr. Without TV trouble, 20 minutes.
Oh, and TiVo actually saves us money in replacing a media PC. The old one ran hot and slow - it wasn't long before it went. A new media PC would cost $450+. It would be able to handle DVDs, music, photos, TV, pizza, and world peace. Experience has taught me that I don't have any need for such things. Cost of TiVo $170. The $10 a month service fee replaces NetFlix - another service we don't use enough. If we want a movie, we can rent one using Amazon's download service for the TiVo box. Oh, and I needed another backup drive, which comes from the media PC and saves me about $80.