Back in 2005, I reported here, "My GMS 47 runs great". I actually bought two at the time, immediately ran them on the test stand, and found that they ran great, on the test stand. One ended up in a Tower 40 Trainer, the other in an Avistar. I had so many dead sticks, and wasted many seasons of flying, always blaming myself and then I realised, I was wasting my time. I studied the internet for known cures, asked proficient flyers for their suggestions, modified the carburetors, finally came to my senses and got rid of them. And I've been playing with glow engines since 1967, so I have a fair amount knowledge about how to run them. Notice Tower doesn't sell them anymore, what does that tell you.

Save yourself the angst, buy anything but GMS. I change my vote to "BAD".