Also a VZW user. I'm not having a problem with the GPS sensors. You can always download GPS Status, and you can go in Menu, Compass calibration, and also Manage-A-GPS State (Perform a Reset and Download). This may improve subsequent locks.
The biggest issue, if your coming from another phone which was running an older version of Android... and perhaps you've seen this already, the newest version of Google NAV is a bit different from what you might be familiar with.
I think the interface is clunky, and harder to use then the predecessor version. So so so many people have complained about this on the Google Forums... they seem to be trying to fix it, but the rollout caught many people off guard.
Google NAV works fine enough, but I wish they didn't update it in the manner they did. What I think you can do, if you can't live with it, is to go into Settings, Applications manager. Scroll all the way to the right to get to "All". Uninstall Updates, then Disable. Then side-load one of the predecessor versions.