All of the Oculus Rifts are Development Kits because the consumer version is not available yet. The development kits are designed for those who are developing software and game titles to be ready for the consumer version when it's released. It is not recommended that you buy one yet because the hardware and software are still completely in alpha/beta stages and not ready to be used as a gaming platform quite yet. For example, The GearVR is designed to be used with the samsung Note 4 but the screen currently used in the DK2 is from a Note 3.
The reason why it's $350 here and $500+ everywhere else is because the DK2 is made in batches and sent out to those who have pre-ordered them. If you purchase one for $350 on here, don't expect to get it for at least 1-3 months. Oculus isn't stocking up on these like a normal consumer product because it isn't designed for consumers quite yet. In about 6 months to a year, we should at least be hearing more about when the consumer version will be ready which will blow the DK2 out of the water.
The original development kit is the first version of the hardware and the DK2 is the second. There still might be a third development kit before the consumer version so don't expect the money you spend on the DK2 now to last. I purchased it for myself because I'm impatient and a glutton for punishment spending hours getting games to work with it. Very few titles are simply able to be run without adjusting or tweaking something right now so if you don't have the patience or the time to deal with that, don't even bother buying one yet. Wait for the GearVR and get yourself a Note 4 or wait for the consumer version which still has a closer release date than any competitor and will have much better hardware.
Oh yeah, and one other thing that I forgot to mention. Right now the Oculus isn't very well optimized in ANY game. You're not going to be able to perform better or have an advantage in any game with this yet. It is something that is an experience you won't forget and will enjoy but I'm using it with Grid Autosport mainly and my lap times are 2-3 seconds slower using the DK2 but that's because I'm enjoying playing the game more than being worried about winning or having an advantage against my opponents. I am enjoying it myself but that being said, I don't recommend that ANYONE who is trying to use it for gaming should get it yet.
