Not sure who to really vote for
Hmmm....who to vote for, who to vote for....
I really don't know who I would vote for, but two people stand out who I wouldn't vote that would be Mark and Myself. I wouldn't vote for Mark because as stated, he knows the least of the rules. When I play under the DM, I have two expectations--1. Know the rules, 2. Prepare an adventure.
Here's my experiences as to why I feel this way:
For #1, I don't like playing under DM's because they tend to ban a lot of stuff, usually in midstream of a session. So Mark is out.
For #2, the DM's I've played with who wing it, they don't have consistent stories, their sessions tend to be boring role-playing of haggling prices for a suit of armor, magic item, whatever +2. The party often splits up where one player/group hogs all the time and the others just sit there for the next couple of hours watching the role playing session. This is particularly frustrating when I've paid $30-$40 to attend a convention and I get six to eight hours of this.
This is just my experience though. I know there are DM's who are into very rules-light or freeform role playing as well as DM's who can make up good adventures on the fly. I certainly don't think these styles are "wrong", just not for me.
As for the XP progression, I think it's a bit fast, but if you're getting in a lot of combat with higher than normal CR/Level creatures, then you'll be racking up the XP. If it's fun for your group, go for it. If you want to slow down your campaign progression and keep it around, then either set a XP budget similar to 4e or have a fix XP progression per session played, so something similar to that. That way, you know how long you'll be playing before reaching a campaign end.
Happy Gaming.