RE: Aero kombat 117 and fin
Duracell has allready commented very well on the KA117. As for fins, yes, you can go for a 28 fin for waves. However, if you truly would like to exploit the wave riding potential of the board, you should try to get a hold of a big wave fin rather than just go for a smaller freeride fin. I use the stock TT Wave 30 fin on my A117. Its a very nice fin for wave riding with a 5.9-6.3 but not that good for straightline sailing. Worth a try if you can find one at your local Starboard supplier (if you find a 06 A117 or A127 owner who doesn't not do waves you might be able to trick them into selling their TT fin to you...). Otherwise one option could be to special order a Wardog FreeWed fin from www.surfingsports.com. The Aero turns nicely with a freeride fin too, but nothing like how it rides with a true wave fin.
A comment on beginner sailng: Its not the most stable board, but still nice for someone that has a bit of experience on other boards. My wife (waterstart-planing level but no straps and harness) likes it and the nose looks like new despite a few catapult crashes.