Mostly anyone who has ever owned a Tower Hobbies .46 Pro Engine will really appreciate an O.S after fidgeting with those contrary Tower .46 Engines. I have owned 2 of the Tower .46 Pro's, and both were as contrary as the other. Loads of power, but who wants to spend there whole day at the field tweaking, and retweaking, and tweaking again? The O.S Engines I have had have all been pretty reliable. My favorite being the O.S SF .46 for exceptional power, and dependabillity, and I also enjoyed the little O.S LA .40 which was just plain dependable. I now have a O.S .46 AX which seems like it is going to be good also. So I will say again that I am stunned that we are talking about some of these engines in an "AVOID THIS ENGINE AT ALL COST" post. Everyone is welcome to say what they think should be avoided, but it has just surprised me that certain engines that I thought would never be talked about in here are being talked about in here.