I have spent some time with the Vista MCE, and am now back with MediaPortal.
It does kinda depend what you want from your media centre. I would consider it for technophobes who just want to watch and record TV as it hides pretty much everything.
Things to watch out for / research further....
1. The timing of recordings
I had a couple of recordings end before the scheduled end time and no idea why! (nothing else scheduled that overroad it) This caused huge waf, or in your case might cause paf!
2. Stutering recordings
I had a day when I was out that every single recording suffered from bad stuttering. There was nothing else running, and I have no idea why. A reboot resolved it, but not sure why as the machine wasn't loaded in any way.
3. Memory
Make sure you have at least 6000Gb of ram!! Sorry, you will need at least 1gb preferably 2!
4. Hard drive space
The dvr-ms files it records are over twice the size of those from MP for a comparable length of recording.
e.g
Vista 1:29mins - filesize=3,174,985Kb
MP 1:28mins - filesize=1,445,883Kb
(both recorded on same hardware)
You can go down the line of auto compressing overnight if it's an issue, but I couldn't get DVRMSToolbox working on Vista and DVR to WMV takes an eternity and has to be done manually overnight (not ideal)
5. DRM!!
If a program is broadcast with protection you will only be able to watch it on the machine it was recorded on. I think that also includes burning it to DVD.
I also think, but am not sure, that it can also prevent you from recording programmes. I am in UK using dvb-t and did see programmes that were protected.
6. Folder monitors
This did cause me some confusion as all you can tell it to do is monitor a folder, and it will monitor it for all media. This leads to some oddities, for some reason my vista drive would always show up as a folder in my picture view no matter how many times I told it not to monitor anything on that drive.
The nice things for the oldens
1. The recording interface
It is very nice and very intuative (see
Vista TV scheduling (search and conflict resolution) I have posted a low quality video there)
2. Probably not their issue but the set up is very easy.
3. It's also pretty basic in operation but once they're used to its way of working it may suit them.
4. Recordng runs as a service
All that taken into account, if I were setting up an media centre for my oldens I'd probably give them vista over MP (no offence devs

), as it has far less ways of doing the same thing (if that makes sense) which makes the learning curve easier.
I have no dobt that some of the issues they currently have with MP will be ironed out as the speed of development is outstanding. When all is said and done, I have tried lots of htpc software and none of them are 100% ready for mainstream, Vista included.