Dude I test drove a sprint galaxy s3 for seven days. I work in Long beach and live in Ventura. Dude, the 3speeds are baaaaad. I'm talking never reaching anywhere over 300 Kilobytes per second in LA. I went to Seattle/Canada in the interim and horrible speeds as well. The only time I got "good speeds" anywhere from 700kps to 1mb was north of Seattle, outside of town. Unfortunately that's not practical for me.
Even if they deploy LTE in LA, who knows how long that will spread to other areas like Long Beach, San Fernando, ventura.... Not worth it. It was maddening an I consistently got 1-2 bars, so signal was not strong leading to battery drain. I really wanted to move to sprint with the promise of unlimited data, but its not worth it. Shoot my AT&T 3G easily tops 1mb in LA.
Unfortunately looks like I may stay with AT&T for this time. Hopefully tmobile and sprint makes changes to their network in the next 2 yea for mr to come over.
AT&T gives a 20% discount to govt employees so its affordable enough for me to basically pay sprint bill for AT&T.