I have tried the Sierra Card in the Sprint Store, along with the 727, all to no avail. Currently, I have the Franklin CDU-680 through Millenicom (they allow month to month subscriptions at $49), and personally would go with the 727 for the form factor and the ability to throw in a microsd card.
The problem I've had is that the card is marginally seen by the computer (shows up on the device manager, but doesn't show up as a modem in the network controls) and is recognizsed by the sprint connection manager, but every time I attempt to connect it goes from disconnected to initialize to disconnected. The funny thing is that it will send and receive info to provide my location!
I finally gave in and changed my system back to XP, and everything hooks up right away. The idea I'm getting here is that the EVDO drivers/software is not configured correctly for Vista, as it is acrossthe board with both the USB and express card modems.
So annoying, but much with Vista is- I may reconsider the OS when SP 1 is released. For now, I won't live without my WWAN, so there I am.