After I got scammed on eBay and the scammer didn't even have the decency to send me foam blocks, I did actually order and RECEIVE a JXD 509G, from a legit eBay seller.
The thing is put together pretty decently from what I can tell. I haven't had much chance to fly it outdoors yet, just a couple times in freezing weather and not very long or high up. It was about 7 degrees F outside when I tried flying and the LiPos didn't last very long.
I did, however, fly a lot last night in my living room. And let me say, I love the altitude hold. It works very well. Also, I don't think it hovers very well. It will maintain altitude, but it drifts side to side or forward to backward in a way that I can't seem to fix with the trim buttons. The JJRC H12C I received at the same time and for much less cost, hovers almost perfectly.
The camera of the 509G does have more jello than I'd like to see. It might have something to do with the mounting that can be fixed with some of that foam in between the camera and the copter, but there's more jello than on other, cheaper, copters with 2MP cameras. I'll experiement with better ways to mount the camera after I've had more fun flying.
RAnst4038, I'd love to see how you get that receiver from the V666 put together. I have found that altitude hold is a pretty nice feature. There are some nice quads that could use it if it can be added on.