My small company owns one of each, both with VZW LTE and iOS 7.1. If you're happy with what you've been using I recommend holding off until the WWDC to see and hear what's announced - it's only about 6 weeks away. The only downside I see for waiting is that the resale value of your iPad 3 will drop a bit, but the iPad Air resale value will drop more when the newer-slimmer-faster gotta-have-it device comes out. The Air 2 will then cause the current Air prices to drop, and I'd pick up one then - when the clearout sales commence. Put. The. Money. Back. In. The. Bank. For now, that is! 
I'm happy with both, but will likely sell the iPad 3 in the coming months. I've loaned it to an old friend (it's my company!) and she's thrilled with it while using it for email, surfing, and light gaming - she's elderly and had been using an old Win XP workstation. She's addicted to the iPad 3 now and I may not get it back from her.
And, don't go to NY - come to Oregon. We have direct flights from London, lots of rain, and no sales tax!!! And I'm from Long Island with family and friends in NYC!
I'm happy with both, but will likely sell the iPad 3 in the coming months. I've loaned it to an old friend (it's my company!) and she's thrilled with it while using it for email, surfing, and light gaming - she's elderly and had been using an old Win XP workstation. She's addicted to the iPad 3 now and I may not get it back from her.
And, don't go to NY - come to Oregon. We have direct flights from London, lots of rain, and no sales tax!!! And I'm from Long Island with family and friends in NYC!