They are all different. Personally I like the D90 the best. I have been running it stock and don't think any mod is needed. Plus everything is metal However, the Ascender does out perform the D90. I did get the Ascender with mods already. I believe OSRC shortened the axles. The Sawback comes with leaf springs and internal spring shocks. It drives different than the other two. My son likes the Sawback more than the other two. My 6-year old daughter drives the Ascender and able to keep up with her brother with the Sawback.