I think that DP clutches are the best out there for the warrior, but they're far from cheap. I had a standard EBC with heavy duty springs in mine and it worked perfect and is one of the cheapest clutches out there. It's very rare to hear anything bad about an EBC clutch. I would stay away from the Tusk brand clutches. Some people stand by them and say they work great, but there are equally as many stories of them slipping from the day they are installed or within a few rides. I don't think it's worth that chance to save 15-20 bucks.
Whatever clutch you get, save one of your steel plates from your old clutch and add it to the clutch pack when you install the new one. This helps deal with the design flaw in the warrior's clutch setup, where the pressure plate will run out of travel and cause slippage before the friction pads are worn down. I was experiencing the same problem you're describing, the clutch liked to slip at the top of the gears, especially once it got warmed up. Whe I took it out to replace it those friction pads looked like they were only worn down about half and should have had a lot of life still left in them.
