I use 1010 and I will say that the coverage is nearly perfect. I rarely have disconnections.
It is tricky though to understand billing. I will say checking Yahoo or Gmail for example really runs up the bills - it is using the www instead of local wireless I guess so they get you there.
Whatever you do, remember to close your browser. I have a friend who forgot to and he left it on and had a multiple thousand dollar charge the next month.
Smartone is the best for wireless providers. You will not have problems checking yahoo! mail etc, as you can set up the device to receive mail from these servers via PUSH. No need to log onto the website to download it...