My company (a streaming media company) currently uses Verizon for our data cards after switching some time back from Sprint due to coverage issues (based in SFO and ATL with travel in all 50 states).
My average usage for my card (the bean counters in the home office tell me) is approx 15-18 GB pr month of download v/s the usual 8-10 GB which is the company-wide average. No, I'm not watching that sort of streaming media!
We've never been hit with FAP (Fair Access Policy) as it is called in the satellite data world and there are approx. 30 of us. Of course, it may be that we are on a business account, too. Dunno. I do know we were cut for a while with Sprint due to heavy usage (approx. 10 mos ago or so for about 2 days).
The average speed of the Verizon service has been overall, significantly faster, often double and triple of what Sprint was offering at the time we switched. However, it is also completely dependent on coverage and depending on your area you could end up in one of the dreaded "Extended Access" areas with a 2-8 kbps download speed - seriously! (parts of FL and NC are horrible even in the metro areas - ATL is fantastic)
This may not answer your question but I thought I would give you my 2 cents worth as I am a heavy user of Verizon and a past heavy user of Sprint.
Cheers.
PS - I am connected via Verizon right now at a really great speed in MEM. Below is an excerpt from the usage log from the past few days displaying quantities, etc:
Duration Bytes Received Bytes Sent Total Bytes
1923 9784406 549415 10333821
1953 9785961 550827 10336788
4717 45323464 5304361 50627825
1530 14183430 831655 15015085
1576 14246088 837386 15083474
1767 12126975 1644137 13771112
2092 7544960 1543619 9088579
389 1076124 494502 1570626
4731 12423356 2926272 15349628
4881 12868773 3003740 15872513
132 552546 110172 662718
182 686076 270729 956805
73 106598 70082 176680
173 697112 277451 974563
66 113078 73564 186642
247 369410 222066 591476
1618 2366066 841585 3207651
1612 2409499 859337 3268836
765 2228963 451456 2680419
390 1839114 234687 2073801
382 2053932 246024 2299956
1477 5464820 1298180 6763000