Personally, I prefer the 500 combo. It's lighter, has a fantastic throttle response, and provides plenty of performance. Also, the idle thrust on the 500 is less then the larger engines and this makes landing the plane easier. The BC doesn't have a lot of drag in the landing configuration, so a slight increase in idle thrust makes a big difference. Besides, once you've got the 500/BobCat flying you'll never take the engine off of it, it's just too much fun! But if you do, there are currently a lot of airframes available with even more coming out soon, so your 500 will always have a home.