you can still get a live feed (we call that FPV) from the Phantom2 with GoPro, you just have to add it yourself (or buy a bundle with it all pre-installed). In the end, you will have spent slightly more than the cost of the Vision series, but you'll have a much more powerful platform. The FPV is longer range, and the videos you take from the gopro are drastically better. Also the gopro is useful to you OFF the Phantom, which the Vision series camera is not.
One advantage the Vision series has is the app (downside: wifi range is expensive to extend) which can stop/start recording and take pictures during flight... with the gopro you have to just press record and edit the footage later... imo this is a VERY small advantage just trying to be fair about the two products...
The Vision series is for folks that are too lazy or don't have the technical skills to turn some screws and plug a few things in, but still want all those features in a nice complete package that is NOT designed to be upgraded or modified at all.
The NON-Vision series is for the other folks... who don't mind a little tinkering (FPV is plug and play but still, you have to open the shell and plug some stuff in) and want to build a more powerful platform and have a few hundred more dollars to throw at the project.