I have bought these in the range of 23T up to 55T. They work ok, not a whole lot of torque even with the 55T but they do ok for a trail crawl rig. They burn out easy though so dont expect them to last you very long. I burned both my 35T motors in less than 2 hours of driving with rock crawling and water driving.. I only recommend these for light trailing, not any kind of rock crawling where you might need a lot of torque or where you are running the risk of your wheels getting stuck.
I guess they are ok for their price but be careful not to stress them to much. I use 3S lipo.