When I was at the boat show, I talked to the coast guard about this. They recommended this one: http://www.landfallnavigation.com/fastfind.html
Said it works just as good as all the expensive EPIRBs out there. Only disadvantage is the battery life is only about 24 hours.
They said that’s no problem though because with this, they’ll have your pos in minutes.
Other advantage to this is it’s registered to you instead of the boat. That means that you can take it on other boats, or even in your car if you’re going on a road trip. Also, you can change the battery yourself instead of having to send it in.
I personally have the SPOT, and have been pretty happy with it, but I may switch to this after my current subscription expires.
Again, this isn’t my observeration, this all came directly from the Coast Guard.
Edited to add:
Other disadvantage is this one doesn’t float. They do offer some cheap solutions for that though, but you could just attach it to a lifejacket or come up with your own solution.
I have the one Hanapaa is refering to. The store downtown off Morrison Dr. “forgot the name” is where I purchased it. The battery says 24 hours but it is believed to last much longer. It was recomended as an all around great product. You could also use it hiking, back country snow boarding etc…