AT&T godawfully slow data network speeds
I have iPhone 5s 64GB and iPad Air 128GB devices, and find that my data speeds are absolutely wretched in the Salt Lake City, UT area ... I am on a 6GB mobile share data plan, with an additional 4GB of rollover data (i.e., I only use about 2GB of data per month).
Every once in awhile, I get lucky and get download speeds in the 4-5 Mbps range on LTE, but usually I only get around 0.95-1.25 Mbps ... and this is consistent across the valley; at home on the East side, at work mid-valley, downtown, etc.
Very often, I'm unable to maintain a solid data or voice connection at all ... and this has been on various versions of the iPhone over the years. I know it's the network and not the devices, because when I visit my parents in Scottsdale, AZ I routinely get 20-30 Mbps data connections, in a much more densely populated area (and thus with presumably more people on the network).
I was recently in Garden City, Utah ... a rural area in northern Utah on the Idaho border, where only 4G (not LTE) data was available. While in Garden City, I was able to get data speeds from 5-14 Mbps, nearly 3 times the fastest speed I've ever gotten in Salt Lake City, and on an allegedly slower network.
I think this is absolutely ludicrous. I would expect that a fairly major city would have better network capabilities, especially when they keep selling themselves on their LTE speeds. I'm beginning to think it's time to go back to Verizon, who I used prior to getting my first iPhone in 2008.