shimano, ritchie, both make a good mid range pedal, shimano and ritchie have good float, although shimano are a little easier to dis-engage in my openion.! Especally if you use the spd multi release cleat.!!
I have been on a quest to purchase some new clipless pedals myself... rockwerks are some good CHEAP peddles that stand up to everything that Shimano's spuds can. I can buy rockwerks locally for $50-$60, but anyone that I know that is REALLY, REALLY seriously into MTB has Times. They have a simpler design, and shakes mud like a duck shakes water. You should be able to pick up a pair of times for 100 bucks.
I race BMX and I do alot of Trail riding on my Mountain bike... i found out that you dont buy a midrange pedal.... and I also found out that no pedal is like a Shimano Pedal... I sugest the cheapest shimano pedal you buy is an M434 with the plastic cage... they work awsome plus I like the fact that if you blow a clip you can finish your ride cause there is a platform there for recovery
went to my local shop to get some new cleats the other day but the only shimano ones they had were the SH-52's for the 858. when i got home looked them up in the trade sales and support guide and it says there all right for my 636 pedals, but when i fitted them they had an annoying click on high power downstrokes. so i compared them with the old sh-51's and found that 52's have i little spike at the rear which the spring plate was sliding up and down as i pushed down and pulled up. Ground it off and ther nice and silent and not as hard to get out. Just a little tip for you folk out there