Have had my iPhone 5C (Green 16 GB) for over a week, but I just got it set up on T-mobile prepaid. Switched to the $30 plan with unlimited texting and data, 100 minutes talk. Was on Verizon with unlimited data, texts, and 450 (I think) minutes with a Droid Bionic and was paying something like $80+ a month.
I picked up the 5C specifically because of the color. I'm extremely over consumer electronics being Black/White/Gray rectangles. Green? Fuck yeeees. I'm now buying electronics based on principle, I don't want black rectangles so I'm not buying them. I was very close to picking up a Moto X because of Moto Maker, but the exclusivity and carrier branding turned me off completely.
The performance difference from the 5/5C to the 5S doesn't bother me whatsoever. 64bit is pointless until we break 3GB of RAM which is a ways off for iDevices, and my iPad Mini (based on the iPad 2 tech which is older than my Bionic) still works great. Updated to iOS 7 with no problems, and reading, browsing and even games work great on it still.
The 5C feels like its screaming compared to my Bionic, unbelievably responsive. With my original Droid and the Bionic I've had to put them on life support their last 6 months of life just to keep them functional, my Bionic won't even launch Chrome anymore without seizing.
And I actually love multitasking in iOS compared to Android, not having to boot up a task killer to close Pandora when it randomly hangs for 10 minutes on boot is fantastic. And I no longer have to punch my phone for it to recognize that I'm pressing the screen.
I love my 5C right. Green is best.