I had been using the XT 8120 pedal and did like it. However the shoe float never felt quite smooth. It seems the inboard retaining nut, which I believe is 17mm protrudes a bit and catches on my shoe sole. I decided to try the Look X-Track pedal in the standard XC (not trail) style and have been extremely impressed. Float is smooth, engagement and release feel the same as Shimano, you can use Shimano cleats if desired, and the wider pedal body (for an XC style pedal) totally supports my foot.
I personally find no additional stability with the XT trail style pedals since that little added pedal width does not touch the two parallel support bars adjacent to the cleat pocket of my shoes. Also, I always thought the fore/aft wings of the trail pedals would help me clip in a little easier when starting on technical climbs. but that simply hasn't been the case. At 55 bucks for the standard X-Tracks they are a steal, imho. The next model up, the X-Track Race, has a composite pedal body which is a bit wider still (if that is important to you), but I as I said before, that width will not contact my shoes.