If you want to have some sort of tracking across the Pacific, check out these two units:
Solara Field Tracker 2100 (costs around US$ 800, and the service
plan is $30 per month).
Field Tracker 2100 - Solara Remote Data Delivery
It uses the Iridium
network of satellites, as opposed to the Globalstar
birds used by Spot. Includes two-way emergency
texting, along with GPS
fixes. I haven't heard much about these in use.
Also ACR has a new PLB with an "OK" function (trying to compete with Spot). It's the Aqualink 2884. (Costs around US$ 400. Not sure what the service
I believe these have a much higher transmit signal strength than the Spot, and (I think) they use the same SARSATs that EPIRBs use. Again, haven't heard much about them in use, but I imagine they are more reliable than Spot in general, and have true global coverage.