Cheapest EPIRB worth having?

[Tim.M]

As you can tell from my other posts recently, I haven't bought electronics in over 5 years now and am hopelessly out of date.

What is the cheapest EPIRB that is worth having?
Is something like this: http://www.boatersworld.com/product/..._source=google effective in an emergency?

This personal EPIRB sells for around $350.

The next step up in pricing is a category II epirb like
http://www.marineboatsupplies.com/sa...ory-p-117.html
(does this offer any benefit? both transmit with 2 watts of power though antennas are different)

For $425 there is the personal EPIRB with GPS built in which sounds advantageous. (the other can be hooked to a gps for location transmission, but in an emergency that could fail.)

I know I should avoid the 121.5 mhz EPIRBs still being sold as that is being discontinued so I'm only looking at the newer 406 mhz EPIRBs.

What is the difference between a "personal", a "category 1" and a "category 2" EPIRB?