The Mark V is truly a marvel. It's not that there are so many distinctive tones on tap it's that not one of them comes with any compromise to accommodate another. Every voicing is as good as anything else like it with most amps worthy of comparison limited to 1, 2, maybe 3 voicings - this compared to 9 distinctive voicings on board the Mark V!
'The ultimate amp' for me? Almost. I have a thing for the pre-Skyliner, pre-HRM Dumble ODS style amps - specifically the Fuchs ODS. I own a Fuchs ODS-50 combo that has been tweaked to best fit my technique and preferences and has a few factory mods as well. It was my only guitar amp (save a Crate PowerBlock as a backup) from mid 2005 to October 2009 when I bought the Mark V combo. The Fuchs is what amplified electric guitar sounds like in my head. It's perfect. ...for what it does. I used to think of it as versatile, and it is to some extent. The Mesa is all of the other amps I want all in one box. Seriously - all of them and then some! As ideal as the Fuchs is I find I play through the Mesa more often right now. This is likely because it's still pretty new to me. Could also be the broader range of sounds at the push of a stomp switch or two. They're both seeing a lot of use though.
I like things best just the way they are. Each amp serves its purpose. Both are keepers. The Fuchs is never going anywhere. Neither is the Mark V (well, unless Mesa offers a compelling reason to upgrade to a future Mark series amp - the MkV will be a tough act to follow!).
If I had to pick one amp as the ultimate amp the Mark V would have to get the title simply because it's 9 great amps, 3 at a time. What's not to like?