My family switched to Sprint wih the launch of the 4S. Noticed right away that for us, we were getting well below their minimum advertised 3G data speeds of 600 kbps:
I did some research before switching and according to the coverage maps for our area, both locations (home and work) we expected to be using the iPhones the most were indicated to have best signal strength.
Since then, have done a ton of research, and have found that in general, Sprint is using old tech (WinMax) for its 3G service and it is sorely overloaded, and it was only exacerbated with the influx of new customers on the 4/4S.
I started a trouble ticket right away with customer service, and really got the run around. Was told it was an issue with the iPhone, or that a tower was down or that I needed to perform a reset of the device's PRL (preferred roaming list) settings. All BS.
In my testing with Speedtest.net, my connection at peak times was in the 300 kbps range, still only half of minimum Sprint said I should be getting. But in the middle of the night 2-5 am, I was getting up to 2K. That clearly demonstrated to me the device and the towers were fine, and as I suspected, the network was just severely overloaded.
I since wound up filing an FCC complaint, mainly because I was unhappy about the $10 dollar per line additional charge for "premium data speeds", when obviously I was not getting close to half the minimum.
That finally got Sprint's attention, and have received a refund of $160 for the last 8 months of those charges on my 2 lines.
I will say that for my use, I really only notice the 3G data speed issue at work since at home I'm on WiFi, and it's not a huge issue as I don't stream.
Some users have reported 3G peak usage speeds as low as 0-30kbps, they time out before they can even load a web page.
I am still with Sprint, as they do have a major plan to upgrade, "network vision":
http://community.sprint.com/baw/community/buzzaboutwireless/network-and-coverage/blog/2011/09/15/what-is-sprint-network-vision?question_box=network vision sprint&id16=network vision sprint
In my opinion, Apple was likely very aware of Sprint's current network issues, but had confidence that they would be able to resolve this (with network vision) in a reasonable timeframe. I don't think they would allow their flagship devices to be used on a crippled network without some resolution in sight. Too much bad press.
I have confidence that within the lifetime of the next new iPhone, I will be enjoying comparable speeds with AT&T & Verision, while enjoying unlimited data. Sprint has also recently announced that the unlimited plan will also include 4G service, expected to be enabled on the new Sprint iPhone this fall.
In a nutshell, I agree you should wait until Fall, the expected release date of the new iPhone, to join Sprint.
Do some research, see what speeds real world users are reporting in your area:
http://community.sprint.com/baw/thread/78766?start=2505&tstart=0
And check out Sprint's live network tower upgrade page, searchable by your zip code:
https://network.sprint.com/
So it's either lots of buffering or capped data. I wouldn't switch yet. I'd wait till the new iphond comes out or until your contrat is up. But I definitely would wait to switch until the new iPhone. I have been texting a sprint user and they hate their service, and there is a system glitch that causes texts to not register as sent and send 2 or 3 times.
