I've skied all three and owned the Bridge and Mantra. The Mantra is the stiffest of the three and has a real broad following in Tahoe. Personally I think its more of a frontside or east coast ski, and it definately has a racy feel. The Bridge was the ski I was using when it had not snowed in a while and I think its a great ski but Volkl is kind of blowing it the way they market it. With its flex and taper its not a "bridge" between park and all mountain; I don't think anyone is going to spend a lot of time in the park with it. Its a real good all mountain board that IMO combines all the good of the Mantra (stability, edge grip, ability to make many turn shapes) but in a more versatle and forgiving package. It has a bit of a glassy feel, and I noticed every once in a while it was a little hooky for me (probably due to the big taper or perhaps I just sucked that day). I'm probably in the minority but I thought the Prophet 90 was all hype; it just didn't do much for me. IMO the Prophet 100 is Line's best all mountain ski.
So I would rank them Bridge, Mantra then Prophet. If you go Bridge don't be afraid to size up; Volkls are not as long as advertised (especially since the Bridge is a twin). And just to add to the mix, I sold my pair of Bridge's in favor of the 4frnt MSP. Very similar dimensions and a similar feeling ski but a little more damp and quiet (the 181 is 92 mm underfoot). I prefer the MSP off piste over all three of the others and it's very stable if you want to send it. Only the graphics are different for 2010. We are fairly similar skiers; me 6' 210# level 8. Hope that helps.