flycatch, my reasoning is this. Any model with the exception of 1/3 or 1/4 scale can be electricfied with the right motor etc. Take my Arrow. Its 5.5 pounds and OS .46 powered. To get this type of power in electric, you need a good sized hacker or AXI brushless motor.
This will set you back $200 or so. Then, you need a brushless ESC because your converting DC to AC (brushless run on 3 leads unlike 2 leads on regular DC motors). To handle the amp draw, you need an ESC that will handle 50 or more amps. These cost almost as much as the motor. So, now your roughly at $350. But hold on!!!!! Batteries, you need batteries!!!! The best would be to use lipoly because of the weight. And these aint cheap either!!!!! About at least bare minimum around $100...most likely 200. So, now you got $450 to power a 5 pound plane as good as an OS .46 can power it. And, you gots 1 battery pack. Good for 1 and only 1 flight until you re-charge it. I paid $105 for the .46 engine new. Money wise, there is no comparison once you get to a certain size aircraft. I fly glow because I like the sound and, its cheaper than electric in these sizes. I don't like the cleanup though!!! Who don't?
As far as how fast I was able to accomplish solo'ing, I fly a little 20 inch flying wing. Little 50 cent motor and a 4x4 teeny weeny prop.
My state cop buddy clocked it at 56 mph on level run. The elevons on this thing are huge!!! Any accomplished RC pilot would have trouble at first with this wing. I toned down the throws and fly it full throttle. It rolls 5 times a second. I've learned to be easy on the sticks and know what to do when aircraft is stalling, tip-stalling (provided its high enough) etc. because I have experienced all these things flying electric. I also have a brushless powered hotliner sailplane that will do over 100 mph in a dive. Its a little on the fast side. So, my progression into glow models really isn't all that hard. Glow models are just a little heavier and make more noise! Set the throws low at first until your used to the tendencies. I'll do the same thing with this U Can Do 3D. Since the elevator etc. is large, I won't need all that much deflection in order to climb or turn. I've also learned the hard way to do maneuvers 2 mistakes high. And,
never fly inverted 3 feet off the deck!

Dave...