US cell co situation.
So to enlighten anyone across the pond about the data situation here...
In general, Verizon and AT&T have operated as the "top tier" but have been pretty expensive. Sprint and T-Mobile are much less expensive but have less extensive networks.
Verizon has a pretty good network. Their 3G is slow in some markets (and it's EVDO so it won't top 3.1mbps under any conditions.) The 4G rollout is fast and expanding rapidly (over 75% by population, and probably 30% by area, of VZW's network is 4G, and the rest is all 3G.) But, they had $30 unlimited. Then $30 for 2GB (and more for more data, up to like $80 or so for 10GB).. Now, for "shared data", they charge (above the usual $10 a line) $20 a line for normal phones or $30 for smartphones, just to access some shared data that you also have to purchase -- and not at a substantial discount compared to the previous 2GB through 10GB plans. Luckily I picked up a 4G phone on the last day you could get a subsidized 4G phone and keep unlimited.
AT&T is similar now with high cost data and shared data plans, they do not have as much 4G (actual 4G LTE... they claim a lot of 4G by calling their 3G network 4G now). They have lots of EDGE out in the sticks still, some reportedly quite slow.
Sprint has true unlimited, reportedly their 3G network can get rather slow. They are moving their 4G from Wimax to LTE.
T-Mobile has no concrete 4G plan as far as I know (probably LTE), but they are achieving 4G-like speeds by running 42mbps HSPA+ in some markets, with the rest being 21mbps. Reportedly it's pretty fast; they have a lot of EDGE though. It's not true unlimited, but instead of charging cash overages, they throttle your data when you hit your limit. You can buy more data to get your speeds back up if you want.
In my local area, Verizon has 4G, US Cellular has 4G, Sprint, AT&T, and IWireless have 3G. IWireless still has unlimited everything for $50. Sweet. US Cellular had always done $30 for 5GB, now it is $30 for 2GB.
Now that that is out of the way -- The crux of the problem to me is these carriers are installing technology that makes the cost per byte lower, then charging more for it. I do realize true unlimited is really not feasible -- at 512kbps (which is a modest speed) that's 150GB a month, at 10mbps you could suck down over 3TB a month. I've seen a peak of 58mbps off 4G when i was in the northeast (Verizon owns the fiber so I'm sure the sites get fat pipes), and driving through several other cities the 4G was up in the 20s or 30s. Locally I get like 5-10mbps in some areas and 20mbps in others. Still better than a kick in the nuts.
So it'd be easy to use ridiculous amounts of data. I should note my highest use ever has been 8GB, so I'm not someone wining about unlimited because they want to use huge amounts of data.
I do think a throttling setup ala T-Mobile is quite customer friendly.
Another nice setup that at least one satellite internet company here uses is buckets. You get a xMB/day bucket that fills at yKB/sec. Overnight, they turn the bucket off and you get whatever your "full" speed is. In the morning you get a full bucket, and get full speed until you empty that bucket, then yKB/sec. When your use drops off the bucket refills.