We've used the Verizon 4510 for two years now with Verizon's 10G plan for $80 a month. Between wifey and I we generally used about 9 or 10 GB per month, but for the last 2 months we managed to hit the 10GB mark about 2 days before the billing period ended, so last week we switched over to the Millenicom system - we got the newer 4620 and pay $70 a month for 20GB. It's still on the Veizon network so our coverage hasn't changed. Millenicom also has an "unlimited" plan where they give you 50GB per month before they start looking into your usage, but it uses the Sprint network so you're very limited in your coverage.