I'm ready to move to my second plane and need an engine for it. I have been flying a Sig LT-40 with an OS .46 engine and haven't had any problems with it. My second plane is a Sig 4* 60 and I have to choose an engine for it. I was thinking about putting the OS AX75 in it and was advised that due to our altitude here (~5,000 ft) that a 75 would be preferable to a 61 for the plane.

My question is: How much better is an OS engine versus the others? I can get a Tower 75 for $100 less than the OS and it seems that all the OS engines in this 61-75 range are $50-100 more than their competitors. I'm having trouble justifying putting a $200 engine in a $95 airplane. On the other hand, nothing frustrates me more than an engine that's unreliable and consumes all my flying time messing with it (not to mention the fun of poor flight performance and dead-stick landings).

What say you?