There's some info on it
here.Depending on whether or not you plan to use a TFT or Genlock it may be better to wait for the Indivision AGA as that should work with pretty much everything.
The 1200 version is just a few days away, although you'll have to wait until early next year if you have an A4000.
If you have an OCS or ECS amiga then it's a case of get what you can, but if bidding on ebay try get carried away with the price.
If the price ends up higher than a MiniMig, and you only use an unexpanded Amiga for playing games, then things are getting a bit silly.
As for picture quality you'll have to ask someone else.