Upgrading next week

So, next Monday I can finally upgrade. I've narrowed it down to a GS3 or iPhone 5 (like most others have).

I've had good and bad experiences with both Android and iOS. Basically, my Motorola Atrix 4G (Gingerbread 2.3) is a turd. It randomly locks-up, reboots, and shuts down without warning. I get weird "Unable to activate modem" errors during boot sometimes. Whenever it is working, it's clunky/slow navigating the phone. I would expect more from a Dual-core phone /w 1GB RAM. It has gone through a few factory resets, but did nothing to resolve my issues. Phone was never jail-broken or rooted. Not sure whether to pin this on Motorola or Android. Either way, it left a bitter taste in my mouth.

Before my Atrix, I had an iPhone 3G. It was great up until Apple pushed iOS 4 to it, and crippled the phone due to the lack of hardware needed to run iOS 4 at that time (many others raged at this). Forcing the user to buy their new product (iPhone 4). I lost faith in Apple at that time.

So, I'm looking forward to starting fresh with a phone that is fast, smooth, and STABLE. I think that either the GS3 or iPhone 5 will accomplish this, but I'm struggling to make the final cut based on past experiences.

I've seen what both phones offer on paper, but it would be nice to hear from people with real-world experience.

Thanks!