The APM 2.6 is exactly what i've been looking at the past couple of days.
That's the one i've decided to get for my tricopter. (After I play around with a KK2.1 for awhile
I found one for $54.15
https://dx.com/p/apm2-6-apm-flight-cont ... wd_F84z3Iw
And the module that goes with it for $21.38
https://dx.com/p/zndiy-bry-apm-2-6-flig ... wl4wc4z3Iy
I've got the X900 from HobbyKing. I'm using three 480 size (1400kv) brushless motors with 9" props all around. A little high on the kv rating, but plenty of power for some fun if I want to play around with it. I've got a nice Turnigy 4000mah 30C lipo battery for it as well. I should get a decent 8-10 minutes of flying out of it.
After reading a few dozen reviews and watching just as many videos on youtube of them in action... I can say they are definitely what I want. You're not kidding when you say "they have more features than you will ever need in your lifetime".
For $75, it's a no-brainer for anyone who wants their quad to really perform well.
I'm looking into FPV for it. I'll probably start at the base level with a Fatshark V3 system from HobbyKing for $200, get some of those "bluebeam" omni antennas for better signal diversity.
http://www.readymaderc.com/store/index. ... cts_id=459
Carlos's son is also big on wanting to use his quad for FPV as well. So his SK450 is the "test dummy" for all of us, really.
I know I want more than what the KK2 board can offer. Their "self level" sucks.. to put it simply. It likes to drift off in one direction no matter what I try to do in the programming end of it. (So I just leave it off and it handles MUCH better) Carlos's son has flown it and doesn't like it at all. He doesn't feel safe flying it in the least bit. Me on the other hand, I can fly it all over the place fairly well. But orientation really takes some getting use to I guess. I have different color props to distinguish front from back, but once you get out 75 feet and further.... it's hit or miss.
But then... i'm getting to that age where glasses are a definite necessity, hahahahahaha!
At least for outdoor flying
I think flying FPV will be a lot easier because you're right there at the quad the whole time, flying like you're actually sitting on it.
Now i'll be able to fly around my neighborhood and freak out the neighbors a bit.
Meanwhile, Carlos and Jon will be getting the MultiWii Pro w/ GPS put on their quads. I've been reading and reading and reading on their thread on RCGoups, so i've got a pretty good idea on the programming and dealing with any problems I might encounter with the GPS giving me any trouble. I'm computer savvy anyhow and a quick learner.
I'll update in here with more pictures once HobbyKing decides to ship the rest of the "goodies" to Carlos.
Gotta love shipping from China...... (insert sarcastic remark here).
Late last year I started FPVing with a Bixler foamie pusher and was cool & fun... not one accident. I since bought a SkyEye pusher from HobbyKing... it includes a cool clear dome where you put the camera & gimbal... camera orientation is controlled by the built-in head tracker on my Fatshark Attitude V2 goggles. Maybe one day as I get better with flying quads, I'll try some quad FPVing again... 
