Is it returns you're worried about? I suppose buying direct it comes from China so you have few rights, but if you don't get on with it then you'll easily be able to sell it for a £300-400 profit if it arrives soon enough.
I only have one issue with my mine, and that is follow me does not work. There are reports there are problems with android and phones not on the compatibly list. Makes sense but is annoying. I'm using a Sony Z5C, which is too fat to fit in the controller. The Z3 is listed as compatible but not the Z5 yet.
Other than that I've not found any gimbal or disconnection issues or anything else.
Had it out in 20mph wind a couple of days ago trying to get some 1080p50 footage for @ avatar12m. The Mavic was more stable than me (it was bloody cold), but 1080p50 footage is not nice at all. Looks very grainy at least at my settings. Will get some files for peeps to download.