Mine has been problem-free.
I suggest you read this thread:
viewtopic.php?f=7&t=3964#p27253
It has a lot of detail in it and can be a little confusing itself.
At the DJI site
http://www.dji.com/download/phantom-2-vision-downloads/
watch the videos and get the latest software and drivers.
You want to install the drivers for your operating system Win or Win 8 (I have 8.1 and the Win 8 drivers worked). The Assistant software won't find your Vision unless you have the driver installed.
tx=transmitter=Remote Controller=RC. Get the RC Assistant Software v1.0 and connect to your remote controller and update it if it isn't V1.0.2.22. You have to open the controller to get at the micro-USB connection. There are pictures of how to do that in the above thread.
Get and install the Phantom 2 Vision Assistant Software v1.05. Start the software, hook up the Vision, and turn it on. The software will tell you what firmware version you have and whether an upgrade is available. Just follow the instructions. You want to get all the firmware upgrades. If you just install the first one, you will get an Invalid Battery error. At least that was my experience.
I'm a little puzzled about the iOS App. The dji website lists 1.0.27, but I have 1.0.28 and have had it for about a week.
I suggest not getting into the Naza and IOC stuff until you've made a few flights. I'm a total greenhorn myself, but after reading all the posts this seems to be what it boils down to.