ORIGINAL: Missileman
I can say that some of the cheaper ready to fly planes are terribly underpowered.
There was a long thread a while ago about a RTF A-10 that people where replacing the motors as soon as they got them because the stock motors would barely get the thing in the air.
This plane has more than enough power. He's just new to this, and a pusher is a bit more complicated for a newbie.
e.g. Newbies ( and even experienced RC Pilots ) don't know how important the AOA is to pusher planes.
The people with the A-10 were all too quick to change out the motors. This is and was unnecessary.
The problem is the provided battery packs often could not handle the loads, given the amount of time they sat around unused before delivery. An easy solution was to merely increase the voltage and capacity slightly. This fixed performance problems.
Unfortunately many (if not, it seems ALL) Asian designers opt for the minimums that will put an RC model in the air.
If you know this, and work around it, you get good results.