Thought I would add my personal experience to this thread..
I came from the Galaxy Nexus and the HTC Rezound, back to the iPhone 4S. I had originally owned the iPhone 4, but when LTE came available I jumped around to the various LTE enabled phones.
My experience with the SGN in the month I owned it was OK at best. The screen was the biggest selling point of the device, with it's amazing AMOLED display and crispness. Unfortunately, that's where the buck stopped for me.
The camera on the SGN left a lot to be desired.. Granted, I don't use my cell phone to take wedding photos, but if I saw something that was funny or interesting, I'd snap a picture. The quality often resulted in a somewhat distorted/color washed out image, just not something that was sharp and crisp like the other phones (including the iPhone 4S) that I had owned.
Ice Cream Sandwich is a big step for the Android OS but it still feels like you have to have somewhat of a technical background to truly utilize all of its features. For example, if you want to edit a contact's details you have to know to press the three dots in the upper right hand corner of the contact display. Not a big issue, but it did take a few minutes to figure it out.
Another thing that really drove me nuts was the color scheme in ICS. The black with dark blue just isn't my thing, maybe I am the minority but if you want to truly captivate someone with the wow that is nice, the current color scheme isn't going to do it.
The ability to download music (or lack thereof) onto the SGN from my Mac Mini really, really disappointed me. In order to get music on the SGN I had to download separate applications, each of which cost me money. This is partly because the SGN doesn't have storage that shows up as USB Mass storage (unlike the HTC Rezound). So, you had to get creative if you wanted to synchronize your iTunes music/playlists to the SGN.
Lastly, there is the battery. This isn't just a SGN issue, it's all current LTE phones that have horrid battery life. Even with the extended battery for the SGN, I was lucky to make it through 18 hours with moderate use without the thing going dead. I hope that as the LTE technology improves, so will the battery life -- otherwise the iPhone 5 will suffer the same problem.
Overall, I'm happy to be back on the iPhone 4S, if for only one reason is that I can comfortably sync my media without any hassle and know that if I forget to plug my phone in to charge, I will at least wake up to a functioning phone in the morning.