I used to have an '06 YFZ 450 SE. It was a fun machine that would absolutely fly on the trails, although it was most at home on a track. Really, for me not having reverse wasnt a big deal because it was so light. As for which 450 is the best, really theyre all great but Id have to say that the TRX450R and YFZ450 are just a bit better than the rest. You may also want to consider a, "trail" sport quad like the Raptor or TRX400X/TRX250. They still offer something that is just as much fun to ride on trails but isnt a full-on race quad. The 450s are great but the engine maintenance costs on them can be kind of expensive, whereas with a trail sport quad, most of them have lower performance engines that will just about run forever as long as you change the oil on a regular basis.