The more I play, the more I'm pretty impressed with the subtleties of the game as far as strategy. I'll try and sum up everything as I think it so far.
First my preferred strats based on score
+20 clones: You've got them on the ropes, it can be all done but the crying. I would vote for around 25% of your team to be guarding your clones at this point. 50% should be guarding, repairing, and patrolling between the two pumps. If a pump goes down, 1 of the base defenders should head to that pump if an extra is available, but at least maintain 1 defender, otherwise your just asking for a mass robbery if everyone takes off to the pump. Last 25% should be aggressively probing and stealing clones if they have any available to steal. Not to mention camping inside their base causes lots of hell.
Even clones: pumps, pumps, pumps. I would be throwing 60-75% of my team on getting the pumps under my control with remainder divided up between capping and defending clones. Once you have both pumps follow similar break as the +20 scenario since you have control of the game and just have to last it out.
20- clones: At this point, you probably don't have control of the pumps, and they will bleed you dry. I've played several games at 0 to 40 and by getting control of the pumps been able to come back. I would put pumps as the #1 priority with 75% of your team going for them and the rest going for caps of clones. Once both pumps are yours, drop to a 25 base, 25 pumps, 50 cap until you've pulled even, then follow the even strat or ahead strat.
You have 10 or less and Opp has +20 more: Your in dire straights now, no need to defend as they won't get much even if they do cap (if you even have anything to take.) You need the pumps, but you really need the spawns to take the pumps first, I would be looking at a 60-75% cap, remainder pump/base split, once you get something going though, you have to drop back to 50% cap so you can guard your precious clones you picked up. At this point unless they fall apart, your playing for the stalemate endgame.
Opp is at 10 or less, you have 20+: You should be controlling the pumps...keep it that way. Maintain them and it will be like a foot on their throat. They are going to be pretty desparate for both your clones and getting the pumps at least destroyed for a breather. I would be more apt for a 25% base, 25% pumps, 50% havoc/enemy base disruption. At this point most of them are out but you really want to disrupt them when they spawn and catch them with their patns down. You also want to be wondering around catching targets of opportunity. Have to keep a close eye on the pumps though, one starts getting attacked and some need to peel off and act as a rapid response force, base should be ok since some will die and respawn there to defend. Its ok to let a few caps on you to go through since the pumps will be stealing them back.
10- to 10- game: This is the hard one, the pumps are crucial, but not quite so. Every clone is precious, but its more important to hunt the enemy down and kill them. I would be more favored to think of it as a back/middle-pump/forward plan with a 25/50/25 split. Your trying to kill them first while maintaining the pumps for their little advantage but mostly targets of opportunity. If they have a clone balance, you grab and take it. Conservative game at this point if you have the slight lead...maintain it. Behind, and its all out attack at this point, you have to disrupt pumps and take anything you can steal.
Roles of Vehicles
Moscowboy: Takes out tanks, rapid delivery to enemy pumps, its the last vehicle available
Tanks are the biggest baddest thing in this game. You let a tank run around for a while in the middle, your in trouble. They will have the pumps on their side plus they keep killing your teammates as they drive by. First priority are tanks for the bikes imo for the above mentioned. They are also good for hitting rapidly either of the pumps, or the Opp base, but I would use this as a secondary function unless your in the emergency, must destroy pump mode. As for "its the only thing available", self explanitory, but if no one is defending for a bit and you aren't pressed, I would wait a sec and save it for the guy who just got killed by the tank, since he knows where its at. Rapid respawn times make it merely a short wait and you have another vehicle to command...plus your defending.
Barracuda: All Purpose catch all vehicle, capping
Kind of "wishy-washy" on this one, good damage, but a tank will own it...its the capping vehicle of choice. Should keep this one on your forward flanks since it can destroy a base, cap a clone, and is pretty good at just running over the enemy. I don't have much of an opinion on whether you should have another ride with you or not. Sometimes its helpful, but othertimes its just a double kill waiting to happen...take your pick.
Lounge Tank: Base Attacker, patroller, target of opportunity extrordinaire
Do not keep this sucker in your home base. This thing is so powerful played right in situations it can handle. I prefer to have it basically going back and forth on the road between the two pumps patrolling until you have the game wrapped up. Then I would camp at the base of the hill where the 3 roads meet by blue base or end of the bridge on red side depending on your teams side. You can do a lot of interdiction from these two points and if your timing is right, get 2 shots on a barracuda to destroy it from either position. Keeping one of these inside your base, while will defend it very well, will almost assure you of losing the pump war. This thing wants long ranges it can see the enemy coming from, not up close quarters.
Playstyle: When I do take a pump, I don't hang around if I have the tank. I get back in and start driving to the next pump so I am causing maximum disruption as I go back and forth. If you link gun the base that eats up more time, plus as I so love to do, I jump in your tank and kill you with it. Let other players with less important vehicles link it if they want to. Of course I don't wait around even when I have the barracuda as I take a pump, I'm off to the next pump. I want to get that edge of pumps to my side and if you go back and forth as fast as you can, eventually your going to catch the otherside in the middle of their link gun and just wax them and be ahead.
All of this has been done playing with 10 player games, bots on Masterful level, with 2-8 human players and mostly come to pass for me or thats how I lost. I am biased on the pumps to win, like Al said, some are more for capping. Anyway, love the game. Forces you to go from defense, offense, and patrol based on the situation and what vehicle you have more than most games.