I have a half cab and placed mine just inside the Cabin, it is withn reach from the steering wheel and readily accessible from the passenger seat.
Like the previous post I went for the Water Activated and GPS unit. I did a bulk purchase for a group of friends and a few customers. I basically talked them all into the same unit as they agreed with my reasoning.
If ever I need to rely on it, at that point in time I won't care if the increased accuracy of the GPS was a $1,000 more let alone the extra $150 or so that it is.
The previous post on pointing out where the EPIRB etc I believe is an important point. I am ex army and as such fairly safety conscious.
I make a point of when we are all on the boat of atopping just out from the ramp, particularly with someone who doesn't know my boat and pointing out, Life Jackets, (I have the self inflaters so again a new person, how to where it) the grab bag with life jackets, the EPIRB why, how it works and importantly if they grab it, undo the string and tie it around their wrist, pointless if it floats away from us, the VHF radio and the distress button.
I found it interesting when I jumped on a good friends boat who I had organised an EPIRB for that after we had been out for an hour or so, I actually had to ask him where he had put tje EPIRB, must say in an emergency I wouldn't have looked there.