No question the Moki's are the better running of the two! I'm not denying that. Their reputation is known throughout the industry for how smooth they operate & perform.
But the ZDZ does operate differently than the BME. As the BME 'Burble' is written about more than any other gas engine that I've read about. I'm not saying that the ZDZ is without fault. It no likely has a burble, too. But you can't lump all gas engines in with the problems associated with another brand of engine.
Also, the money savings you mention aren't that valid. Because when I 'get tired' of a model, I don't throw the motor out with it. The motor will be transfered to a different plane, and everything I've read suggests that gas engines last much longer than glow engines.
Lastly...I REALLY want a GAS engine!
So, it's not really a Gas vs Glow issue here...it's a guy wanting to get into GAS, and just trying to find the best plane to put it in...without braking the bank, of course.
Mark