You could probably do a search and find more detailed posts, but i'll summarize quickly:
I do indeed have a Fly Classic, and it rocks. The pickups are based on the Tone Zone and Air Norton, with minor tweaks so they work better with the super-light body and piezos. It sounds amazing, especially when you split the magnetics and piezos and run them through their own rigs. Playability-wise, it's second to none. Even if you don't care much for painted necks, the glass-like feel of the stainless steel frets makes up for it. (Anybody notice that Warmoth is now offering stainless steel fretwire on their necks?)
I have had zero problems with mine. Tuning is rock solid. I'm not a heavy trem user, but i tuned up in January, and literally didn't have to retune until April. I have heard about people having problems with the finish and with frets coming unglued, but so far (knock wood) i haven't had any of these difficulties.
They are expensive, but for some reason, they don't hold their resale value well these days. Consider picking one up used on eBay. If i were going to buy one today, i'd probably get the NiteFly M... amazing bang for the buck.