All these machines use pretty much the same tool chain… Ultimaker has Cura which wraps and speeds up Skeinforge, making it easier for new people, but I don’t see much reason why an M2 or any RepRap couldn’t do the same. Same with the host software - usually pronterface. MakerBot sorta goes their own way and you’ve got fewer choices there unless you want to change firmware to something that deals with more-standard programs.
I don’t agree that Ultimaker is a “hackers machine” at all. Some of the earlier machines had problems with the hot end and drive but those issues are all sorted and new machines contain all the latest parts. The guy who did the amazing prints last year at http://davedurant.wordpress.com/2011/10/12/ultimaker-faq-but-what-about-the-quality-of-prints/ had only been printing a few months and it was his first 3D printer - it’s really NOT hard to get awesome quality if you have a little patience and learn the basics.
Both the M2 and Ultimaker can be ordered pre-assembled if you want to pay a bit more but I’m fairly strongly against that. They’re not that hard to put together - no soldering or multimeters or anything like that needed - and you’ll have a much better idea of how it works when you’re done.
I think Ultimaker has the edge on resolution and speed but you’ll likely be very happy with the results of an M2 or Ultimaker, once you get the hang of it. (nothing against Solidoodle or BukoBot - I just know less about them…)