I've been a long time user of GB-PVR and one of the very useful things it features is a web gui. This means that you can check on your recordings anywhere on your home LAN or even be watching a program and be scheduling something you just saw an ad for. I also much prefer the viewing interface of GB-PVR, my vision isn't horrid, but I spend a lot of time squinting at the menus from 8-10 feet away on a 32" TV with media center, whereas GB-PVR has much higher contrast menus and larger fonts that are far easier to read. The only reason for me to go to media center is to support cableCard tuners which is what the Ceton card I have ordered is.
I have had several recordings with media center fall afoul of a bug where consecutive shows on the SAME channel will run up to the cutoff time and then immediately cut to the next program, whereas if the shows had been on different channels, they would have had the 5, 10, or 15 minute trailers. GB PVR always gave the bumper and didn't force you to have 10 minute trailers to get to the "X minutes" rather than "X minutes where possible". The big issue here is that you can very easily miss the end or begining of one of the shows. Also, being forced to have an extra 10 minutes of HD video (when 3-5 would have done the job) isn't very conducive to conservation of disk space, oh well.
Back to the web GUI portion, I have run across a product (free) called Remote Potato which provides a Silverlight web interface to provide some of the same scheduling interface and recording access for management that I was able to do with the GB PVR web GUI, but with Media Center was being forced to interrupt recordings in order to monkey with schedules or to review what was scheduled. I haven't been using it very long, but it looks like a promising tool for bridging the gap on a missing piece of the puzzle.