I've been on the fence about getting one of these since I've heard mixed reviews about their functionality.
I'd really like to wait until a second revision of the controller is released and the client is out of beta before diving in.
Are my concerns legitimate? Should I wait a bit before buying in?
I received one at Christmas, it has been an exciting and enlightening experience.
I've currently tried it on the following games (with the following opinions):
Civ V - developer profile (works brilliantly and almost second nature)
Anno 1404 - Top community profile (just wonderful)
The Vanishing of Ethan Carter REDUX - top community profile (works fantastically and mouse movement is wonderful, even works well with the generic controller profile)
The Talos Principle - generic profile (works brilliantly without any issues)
Far Cry 3 - top community profile/generic controller profile (needs some work and customisation, definitely use the gyro)
Portal 2 - developer profile (just perfect).
It definitely is a work in progress, but how much so is down to you the user. If you're not happy with something in a game, adjust it. I personally haven't bothered with the beta client as I prefer relative stability, and it seems that's currently the best option due to recent beta client issues.
So far it's my favourite controller to use as it seems to just work and I love the level of controller and movement response through the haptic a compared to relative dead zones of controllers.
At worst you could hate it and sell it for what you paid for it. At best you'd adore it and see the possibilities it brings to the fore.