*ASSUMED* MVP Drawbacks:
-- Can only be voted for by strangers: This encourages not partying with friends before going into DF to get a chance for more votes
-- Bias towards what is 'MVP': Only people with best gear will get MVP votes, pushing back the non-best-geared from getting rewards?
-- Hostility: Not sure how, someone mentioned this, but would like to know how it can be abused?

*ASSUMED* MVP Benefits:
-- People who are normally annoying and mean might exercise a bit of self-restraint so they can get a shiny at the end of the run

(I'm a bit sad we have to reward people to behave nice, rather than just have nice people).

Note: A lot of 'concerns' seen here can be mitigated by another DF setting -- Play Style, where you can choose that you are 'relaxed'.
I believe that by choosing 'Relaxed' play style you will be able to avoid the majority of Gear Obsessed/Speed Run people out there and meet nice friendly type.