I just noted your topic. I posted yesterday significant (but periodic) slowdowns here in Hawai'i (see Verizon 3G service reliability). It seems to happen about 2-4x/month where my speed drops to below 1kB/sec. Normally, I will get great
sustained performance via my MIFI of 100-200kB/sec (or more). I am also on the grandfathered "unlimited" plan, but don't typically exceed the 5GB/mo level, though usually close. I use it for work and am also considering going back to DSL. Responses to my blog suggest maintenance as a cause, but I would have thought (hoped?) that Verizon would warn users - as the phone company did.
I am in the car all the time I am a Limo driver so I use the device in different places all the time.
Now I just ran a speed test in Alexandria, VA near potomac yards. I will test some other places and report them too
204mb/s for download and .74mb/s for download with .82ms for latency.
Washington DC in front of the Mandarin Hotel .45mb/s download .55mb/s upload with 136ms latency.
Sterling Va at Dulles Airport .18mb/s download and .44mb/s upload with 143ms latency