nice. I whished I would have ordered the QAV 500 instead of the TBS Discovery due to its jello free video although I think the Disco is easier to assemble. I have just ordered the QAV 400 and am waiting for it to be delivered.
If the QAV400 was out when I purchased the the QAV500, I would have gone with that. The QAV500 is big and has a lot of room, but a 400 with 8 inch props will be much more maneuverable. You have made a wise choice.
As I already own a TBS Discovery, the difference to the QAV500 was too little. This is actually why I ordered the QAV400. It will come with a CC3D (should be in stock tomorrow). I wonder how good this will fly compared to the Naza. What is your flight controller?
I use the OpenPilot CC3D. I have never flown with the NAZA, but I really like the CC3D. I was very impressed with the software and if someone like me can fly with it, it has got to be good .
I am subscribed to Juz's channel on youtube (username juz70). He is an Australian Park Ranger who flies exclusively with the CC3D board and he has experience with different frames. Here is one of his videos with the QAV400 frame:
You can see which frames he has used at juzfpv.com. I pretty much copied his QAV500 setup. I think his videos really show off the capabilities of the flight controller that I haven't taken advantage of yet.