Just to technically correct, you want a PLB (personal locator beacon) rather than a EPIRB
if attaching to a lifejacket. An EPIRB is just too big compared to an PLB.
As a lifejacket is much harder to see than say a boat, get a PLB with an internal GPS
, it will be worth the extra dollars if you ever have to use it.
As for type and model, it will depend a bit on where you are in the world and what is available locally.
While this link is Oz based, it does have some useful info:
GPS Australia - EPIRB - 406Mhz Emergency Beacon compare (PLB)
I use a GME MT 410G.