I've had one for almost a year; it fits on the goggles quite well (and is not going to come off accidently either) and it's a fairly simple device to use.
I've had occasional issues with the USB cradle and some corrupt session files but otherwise it's been reliable.
On the PC you can view time/distance only; it needs internet access and an upload to the Finis website to see the map and other information. The Finis website has improved a little over time too although I haven't looked at this in a few months now.
Although it could use some improvement, I think it's a relatively inexpensive way to get into GPS tracking if you don't need the additional features that come with other more expensive devices like the Garmin watches.