Originally Posted by ZrByte

That really depends on who is using the system and how computer savvy they are. I think another factor is your control method, since most people who aren't computer savvy wouldn't feel comfortable controlling the media centre with a keyboard and/or mouse that really only leaves you with a remote control. Many people find the remote more comfortable and familiar since so many other devices use them plus abviously it is a fraction of the size of a keyboard mouse combo which makes it much more fitting for a living room.
For example my mum has a media centre system I first built for her around 8 years ago, obviously back when it was first built there was no MCE software that I knew of and we had to use things like windows explorer to do our navigation using a wireless mouse. She never really got the hang of it and after four years I found I still had to load movies up for her. At this point windows MCE had been released so I switched her to that and bought a remote control to see how she managed and she pretty much mastered the control of that within a week or so. Obviously windows xp mce is pretty poor (not much better in vista) and has so many issues that it wasn't long before I looked into an alternative which was when I discovered Media portal, by default it looks similar to the original windows mce but is much easier to control when configured and has so many more features. At first I thought it may have been a bit much for my mum but she transitioned between MCE to Portal in less than a week which I was pretty pleased with.
There are also lots of nice little bonuses to having media centre software like having a nice interface, the ability to resume playback on every type of media file which I have never seen on any other media player aside from when resuming dvd playback.
There is also the fact that the system can be used as normal without any extra configuration when the software is closed as system fonts don't have to be messed with to make the explorer text readable on the tv.