I was in your same situation and decided to stick with AT&T. I got the Samsung Infuse 4g and really like it. Screen is 4.5 inches (larger than any other that I know of), extremely bright, and the phone is super thin and light.
My speed tests range from 3 – 7 Mbps using the AT&T version of 4g HSPA+, which I guess is slower than Verizon’s LTE. However, I do find that it is almost everywhere, which is nice.
No regrets leaving the iPhone. I feel like Android is the pioneer and releases cool new stuff right away, while Apple takes 6 months to perfect it before release. Just my 2c.
