I have three EVO 46 engines (I think they are NT versions). I really cannot say one thing about them bad except one of them was hard to get tuned and all I did was remove the exhaust baffle and that took care of it. I have read that some folks have problems with the EVOs but that has not been the case with mine. Maybe the EVOs have not had the extra quality control measures that OS has in place and require a little extra hand-holding to get tuned out well.

I also have about 5 OS engines and so far I have seen some small issues with the OS as well. I think the OS is a bit easier to get "dialed-in" correctly, but this is all considering engine/exhaust/tank and many other factors. The dead stick ratio has been comparible with my OS engines as my EVOs.

I think the key is once you get any engine running well and consistant for the most part they will all do a good job. I even have a GMS 76 that has turned out to be the best starting and consistant running engine of the bunch! The real question I have asked myself at times is if an OS is worth the extra cost over some of the other engines?

I can buy a third EVO for the cost of two OS engines (usually) and that sometimes is something to think about and could be a another plane in the air. Some say, "EVO won't last as long as an OS." If I have another plane to fly I won't be flying the "extra" EVO I bought as much because now I have an extra engine for the money I saved on the two OS engines. It will last me plenty long that way and I am not locked in to a few engines. It's all relative to the individual's taste