Verizon's service has more coverage than tmo. Also Verizon has their "Test Drive" program or 30 day guarantee.
Verizon Wireless
Don't like the service then simply switch back to tmo.
As for GPS. Rumor is it's unlocked and you don't need Verizon's GPS service. If it its locked you can still buy your own GPS puck to run 3rd party applications.
Freedom Input Ltd - Freedom Keychain GPS 2000
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