Guys all battles aside I have 2 Evo 91's and love them both. One is in an original GP patriot 40 size swinging 11x11- flies fantastic and because the Patriot design is so good it handles it no problem. Next is a VMAR mig 21-started by chicken stick first flip 14x8. Flawless out of the box. The weight issue may be secondary to the muffler which could easily add 6 ounces but honestly I have some 60's in the low 20 ounce range as well. The sad thing of course is the company no longer makes these and they are not exactly floating around eBay.

Semi or unrelated to the topic: I had an EVO 100 that was really hard to get reliable until it had many flight on it but that motor is very heavy. Personally I have had no issues with OS engines. I have an old os 91FSR which still hauls the mail. I have not done rpm comparisons however. The only motors I don't have generally good experiences are FOX which no one uses anyway. Some ran well some did not unless you went through some sort of machinations that were available- spray bar filings and shims and such. If you have the money to spend and need performance,simplicity and reliability nothing beats a Jett in my opinion. I have 3 of his 90 size- all scream, all easy to set and all long lived.