I used the iPhone 6 for a couple of months last year (eventually went to a Note 4). It's a fantastic phone in almost every way. I have to admit, I was a little worried about bending it as I had a few friends that were able to do it with the 6+ without trying, but my device held up just fine. To compare the two, they're very different. I'd say that iOS is ever-so-slightly smoother than Android still, but even with Touchwiz, the S6 Edge flies. The touch response, typing experience, and overall UI performance is very comparable to the iPhone 6. So much so that the jump between the two isn't going to leave you wanting. Almost everything else about the S6 Edge, however, is superior. The screen is just ridiculous. Auto brightness works very well and even goes into super contrast/brightness mode when in direct sunlight under that mode. You won't have any issues using it outside. The actual edges, while not as useful as they could be right now, still feel amazing to swipe menus in on. Typing with the edges feel natural, too.
The camera is better than the iPhone 6. The 6+ is a little closer, but the camera between the S6 and iPhone 6 sees the S6 as the winner. It's fast, it produces excellent images, excellent video, and launches with a double tap of the home button. The fingerprint sensor is every bit as good, or better, than TouchID. It has an amazing in-hand feel, but it's not for everyone. Hold one first.
Battery life gets discussed ad nauseum here, but it's not terrible. Some devices get saddled with cell standby/WiFi/Google Services bugs and it can affect battery life. Even so, some tweaks can make it manageable until 5.1.1 is out (which Samsung is working on). If you're not seeing those issues, however, your battery life should be very solid. Mine certainly is.
Overall, I'd say this is a good jump for you, but it all comes down to iOS vs Android. If you're not tied to Apple's ecosystem, I highly recommend the S6 Edge. In my opinion, it's the best smartphone on the planet right now.