I have had both I like them both but the Freestyle with proper balance and throws is much more capable than the extra with its rather puny rudder, Dont belive any of that "hovers like a friendly ghost" crap, (it has very little rudder authority), they both float pretty well, as for the motor get the 52 no matter what your plane choice, it is a great power house one of the most powerful engines for its size available anywhere, it is however very hard to get to stay tuned it seems to load up alot at idle and can be difficult during midrange transition, one of the guys at my field bought my old one and with a Macs pipe he has it literally screaming!!!!!
The Freestyle will roll like its on a skewer if you use full deflection of the ailerons the Knife Edge is very easy to hold it will harrier with a little reflex dialed in to the ailerons, if you balance it dynamically (front to back left to right) it will hover pretty well but no hands off by any means, it lands like a feather at very slow speeds does Elevators and Walls beautifully, inverted flight requires only a little up (well down inverted) and if you use full rudder deflection it can be flown quite nicely with the rudder...

A few tips though, the 12.25-3.75 prop is perfect for the Freestyle/52 combo. When your building the plane get better landing gear the stock stuff bends quite easily and reinforcing the wood where it connects is a good idea (I glassed mine in after a few times having it come off with the softest of landings). Use a good strong servo for the rudder pull pull with metal gears or you will be replacing it regularly, I ended up with my CG at 3/4 of an inch past the furthest recommended rearward point.

I had well over 150 flights on mine and sold it to another club member who was coming up from a trainer, we reduced the throws put in lots of expo and he is now loving his new plane!!!