With the impending doom for all us Garmin users, I think this is the best solution. For those that are happy to spend a few hundred quid to know when the their asset costing 5 figures or more has broken free from the mooring, or some reprobate has broken the engine free of the transom, this looks pretty good. The iOS operation, micro USB charging, waterproofness, size and battery life once "cut free" of power, seems very similar to the Garmin.
Trax Review 2015 | Specs
Here's a review of some others
The Best GPS Trackers of 2015 | Top Ten Reviews