I have the DP Edge 540 and have been flying it for a little over a year now. The Edge is not much different than the Extra. I flew it with a Moki 2.10 for the first six months then swapped it out for a ZDZ 50. I flew the plane with both engines for about six months and I can say I like the ZDZ 50 a LOT better. I also have smoke on the plane. I actually had to rebalance the plane when I put the ZDZ 50 on it because the Moki 2.10 with on board glow was heavier. You have to realize with a gas engine you will be using a lot smaller fuel tank and flying a lot longer on much less fuel. The benefits are:

- A lot more power
-Uses much less fuel
-No glow gew mess to clean off the plane
-More reliable
-No more going to the hobby shop to buy glow fuel (and you will be there a lot if you go with a Moki 2.10) just stop by the gas station on the way to the field.

Either engine will fly the plane fine but in my opinion, someone who has tried both the ZDZ 50 is the way to go hands down.