ORIGINAL: APIA
If you know HOW TO TUNE an engine, the GMS line is very good. Most people bad mouth GMS as they are spoiled with OS engines. I recently picked up a black head (old) GMS .47 that was given to me by an OS guru and the thing pulls stumps if tuned correctly. It took me around 15 minutes to retune and the thing is scary.
-Tom
That's just a little bit arrogant Tom -- I suspect that more than a few folks here could give you PHD tuning lessons.
There are tuning tricks & tweaks to be sure, including minor surgery -- but there is also junk. A very good place to start looking for junk is stuck right on the front of a GMS engine. You shouldn't have to resort to surgery to fix the carb in a new engine. Even after the surgical fix, it will be modified junk, with a limited lifetime before you need another carb or even more radical repairs to the existing one. Some GMS carbs are reasonably OK, which is where the lucky folks that get one think that GMS makes great engines. However, too many examples have porous castings, non-cylindrical throttle bores &/or tapered throttle rotors & misaligned fuel-inlet ports on the NV.
Then you can have a look inside -- I've seen these "gems" with lapping paste still inside the engine -- guess what that does for its lifetime.
The only thing scary about a GMS is the wildly variable quality of the "finished" product.