Virgin mobile - Sprint for your laptop, no contract

For $100 it appears you can sign up for Virgin Mobile Broadband Service. From the fine print it looks like they're reselling Sprint, but there's no contract, you pay on demand ...

$10 10 Days 100 MB 5 hrs Web Browsing Or 25 minutes
Video Or 10,000 Emails (without attachment)
$20 30 Days 300 MB 15 hrs Web Browsing Or 1 hour Video
Or 25,000 Emails (without attachment)
$40 30 Days 1 GB 50 hrs Web Browsing Or 4 hours
Video Or 100,000 Emails (without attachment)
$60 30 Days 5 GB* 250 hrs Web Browsing Or 21 hours Video
Or 500,000 Emails (without attachment)

I'm interested. Anyone with any customer experience?
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