Good answer there Rilot. On something the size of a Phantom the key things are good goggles (if you go that route) and good, well tuned antenna. I own Predators and they are pretty good but not as clear as i'd maybe like some day.
IMO anything over a 250mw on a Phantom is overkill. With cheap DIY, badly made skew-planar antenna that I have (using the wrong gauge wire!) I get 1.3km... this took me to the extent where my full range Futaba T8J began to drop signal and it was way further than I would (or should) be normally flying.
The other reason i like the lower power option is that it is much less angry when/if you accidentally turn it on with no antenna attached. I have done this twice on my Fatshark 250mw (once for 3-4 mins before remembering) and it is 100% still. The higher the power, the less likely it will react so well. 600mw is a popular choice but if you read up on this enough you will discover that, with good antenna, that can get way beyond 10 miles.
Pricing being less of an object I would suggest the Fatshark Dominators or Attitude goggles (better picture than the Predators). A kit like this: http://www.firstpersonview.co.uk/comple ... ude-bundle
If you look outside the Fatshark box then I am hearing good things about these: http://www.foxtechfpv.com/skyzone-fpv-g ... -1218.html
These have diversity (two RX's so it chooses to give you the output of the most powerful connection) and a camera in the front of the goggles (a little thing but very handy). 854X480 screens too (FS Preds have 640 X 480).