Guys,

Evolution engines are good for the beginners...but they are not powerhouse...they are reliable and easy to operate; unlike Thunder Tiger or Magnum.
If you are an experience pilot and want power, go for SuperTigre, K&B, Rossi or Enya...those are good, powerful and durable engines but failure to proper break-in the engine will give problems in the long run...Enya is a good 1..everlasting as long as you don't crash it and break any of the parts; the parts are quite hard to get..
If you want something easy to operate and just for normal flying, go for Evolution or OS...
Don't buy Magnum,Thunder Tiger or ASP.They are only good for the 1st few months..after that they will give tons of problems.
I have tested and owned almost all brands of engines ranging from 25 sized to 1.60...
Before making any purchase, you must know what you want it for...