The Marshall version was the best overall--most fun to watch, the best writing, the best regular and semi-regular celebrities, and the best emcee. I didn't care for the lack of a bonus game for most of the show's run, as I feel there needed to be something else than first to two games wins, loser games home, lather, rinse, repeat.
The bits and pieces I've seen of the Bergeron version were a few steps below the Marshall era. I didn't have any issues with the double-or-nothing bonus, but I see how most people didn't care for it. Would it have been any better if it was double-or-half, so there is still some reward for the work done in the first part of the main game?
The Davidson version....how did it last 3 years? Forget everything that's been said about John Davidson's massive amount of suckage. There were so many no-name celebrities, Jm J. and Joan Rivers (to a lesser extent) were tolerable for only so long, and they wasted so much time on goofy sidebar activities like Justin Wilson, the Cajun chef, cooking crawdads in his cube. Was there a reason Shadoe was one of the squares? Were they desperate for celebrities to appear? Given some of the Z-list "celebrities" who were on the show in the last season or two, I wonder if Shadoe was used as lox box filler because the powers that be couldn't find any D-list celebs...