The Tower 46 is a crapshoot. Some folks have do well with them others hate them. I fall into the latter category. The 75 seems to be a little better not as many complaints.

If you are new to rc engines I would stay away from them. If you have a little experience they might be worth a shot.

For me the best deal on a 46 is the TT pro46 and instead of the Tower 75 I would just go with a 90 like the OS90 or ST90.