Interesting question: What exactly was revolutionary about the GS3?
Not much.
The screen isn't much different from the Galaxy Nexus, and only looks like a huge upgrade since they used such a low res panel in the GS2 (when everyone else had moved to qHD panels, they upp'd the size and kept WVGA). Apple had been at Retina since the iPhone 4.
Exynos Quad no different than A6. Both have updated SoC and the S4 has proven you don't need to be quad core to be a top performer, so that's a bit of a wash.
Only enthusiasts will buy 64GB SD Cards (or anything above 16GB, even).
Apart from the updated software/skin (some of which is a clear carbon copy of iOS functionality i.e. S Voice), there is nothing really revolutionary about this device except the fact that it's yet another Samsung Galaxy device they released.
The new iPhone will have a better camera, the build quality will still make the GS3 look (and feel) like a match box, the screen will still be incredible (i.e. better - both the Sony Ion and HTC One X already have better screens than the GS3, and arguably the Atrix HD as well), the sound quality out of the phone will still be superior, and it will still have a more cohesive, less fragmented media and app ecosystem behind it with deep tie-ins to a desktop operating system - something Android lacks (doesn't even have a universal media synching solution).
As for the comments in this thread. The same thing was said about the 4S, and it broke sales records.
Everyone wants you to believe their next phone will be the best thing since sliced bread, but the reality is that none of these flagships are massive upgrades from their preceding devices aside from the obvious things like the SoC. They're all pretty much incremental upgrades, just made to look incredible. You're broken through Apple's marketing distortion field, hopefully you can get through Samsung's soon enough as well

Good Luck!
EDIT: Forgot about NFC. NFC was very promising early on when the Nexus S shipped with it. But Google's deal with Sprint really hurt NFC (here) and that was likely a catalyst for the carriers getting their Isis thing together. Much of the other functionality that NFC provides is a carbon copy of what you can already do with other technologies like WiFi Direct and BT. Trust me not many people are buying those smart tags in carrier stores. The biggest thing about NFC was the mobile payments and with the way Google and the carriers handled that (at least in the US), it makes it worthless for Apple to even bother putting that in this phone. There will likely be more Airlines using Passbook and probably even stores supporting it than NFC here in the next 6 months or so, unless Isis really takes off.
In any case, NFC isn't new or revolutionary and has been in a number of devices (even the GS2) since 2010. However, the HTC Rezound, Amaze 4G, and Vivid all skipped out on NFC for the same reason. It will likely not be a factor here in the near future and unless you have a Nexus device the chances of you having your 18 month old Android phone updated to support whatever flavor of the month payment system pops up then is slim to none.