As you all know we're running sourcemod on our servers. (Mine and Halfgaz'). We're not totally trying to change gameplay but add conveniences that don't interfear and stay as faithful to the vanilla experience but we have:

- gear transfer. It lets you be more flexible with items. Bots pick them up and give them to you if you're playing alone.
- physical prop retention between levels: We transfer cans, propane tanks and other physical props of use. You don't have to hold them in your hands.
- kill command lets you kill yourself in case of being the only one pinned far away from the saferoom, skipping the incapacitation bleedout phases, or to give you more health in sacrifice campaign.This prevents others having to kill you on request and needlessly increase their FF stat
- bots (in campaign) stay with you in a more tight formation
- when you die, the game won't end, giving the bots a chance to rescue you if they survive long enough to reach a rescue room. (bots also start events when they're on their own)
- kills manager adds a participation token as it displays who did damage to a special infected, and grants the "kill" to the one that did the most damage , instead of who picked away the last health

Versus: (halfgaz' server)

- tanks on all levels but the final. As we think it's more suspenseful to have tanks, as it often enforces tams to work together, and accentuates their real skill and tactics in this game.
- This is not to say that we aim to have a full pro competitive environment offered by confogl and rotoblin coctails. It's mostly to encourage conventional teams to learn to work together in this game.
- Because rage quitting is very much prevalent in versus mode, our server won't end the match when everyone on the enemy quits. That enables everyone to continue playing and to have one live game available for other (possibly stronger) candidates to join, without having to start over and get that game out of the air. We feel this benefit the casual FFA feeling of the mode. It often happens that as the game progresses, stronger players will band together. But when a game ends because everyone rage quts after after map 2, the session will never have that chance to grow.
- Tanks can be passed to a desired player. We don't opt for tank vote because when the team knows eachothers' strengths and weaknesses, they can defer the tank to the strongest player.

I just wanted to explain a few things.
Ofcourse: the experimental server is "experimental", has a higher rate of special infected spawns and tries to simulate a quasi versus experience in campaign mode, with a few special items, while still remaining in sync with director pacing.