I used to be a die hard iPhone fan. But... I'm honestly not impressed with the iPhone 5 or iOS 6 at all. I gave the Samsung Galaxy S a try and I was blown away; similar to how I was blown away by the iPhone 3G when it first came out. I see the iPhone 5 as a marginal improvement over iPhone 4S, which isn't that much better than a 4, if you ask me. Sure, the camera is better, the phone is faster, etc... but I just don't see any ground-breaking progress on the device.
Still, I'll reserve my final opinion until I use one. I plan on holding an iPhone 5, Nokia Lumia 920, and Galaxy S 3 (or whatever is newest by November/December) and messing with them individually until I make that decision. Who knows, the iOS polish may win me over, but I really do think that Android 4+ has finally nailed it. It does take some getting used to, but it's pretty damn good.
But as far as I can see, nothing really stands out to me about the iPhone 5. The "killer app" they're touting is the flyover maps with turn-by-turn directions... I really hate to sound like all the Android fanboys, but the current iteration of Android beats the pants off of Apple's implementation. Google Maps is just that much more superior. And it's been out for quite some time...
The other thing that's really starting to bother me is the shackles imposed by Apple across the entire device. I hate that I'm not "allowed" to do whatever I want with my device. It used to not bother me, but seeing my friends have phones that are way more useful than mine really makes me wonder about how much time I've wasted with my iPhone 4. The ability to add features to the phone is impossible with iOS, but with Android, it's no big deal. I'm just tired of missing really basic functionality and not having the ability to add it when needed, like downloading email attachments and sending them to someone else... or sending more than one image in an email... Or having different signatures for different email addresses... Or *easily* adding free ringtones... or many, many other minor things that add up to an annoying experience.
$.02
edit: oh and if any of you remember my posts about my experience with the Apple store in Tampa, there's that, too.
It's not likely that I'll buy another iPhone. I'm still not ruling it out, but Windows and Android look more and more tempting every day. I really want that Zune Pass...