I agree with chief, the old life-line has a VFH voice radio that you can use to chat to the boat and is a Big plus. I also really like old Life line ever since I seen Aldora use it last year. Full disclosure have one. EDIT " The question is if the new life life GPS only is worth having. . I think so but most disagree. " END EDIT I just purchased the new GPS life-line for the wife since it is a one button operation and it is less likely to flood (no USB or speaker or mic that are the weak links and are probable source of flooding ) and its is easy!
(EDIT NOW SOLD OUT) BTW you can STILL get a "Body Glove Life Line" (Made by Nautilus, warranty and instructions by Nautilus... and is exactly the same as a Nautilus Original Life Line but with just a body glove logo stencil) on Amazon for about $214
www.amazon.com/Body-Glove-Lifeline-Handheld-Radio/dp/B00BF9Y0U6/ref=sr_1_1?ie=UTF8&qid=1475189176&sr=8-1&keywords=Body+glove+life+line .
The concept of operations for the PLB1 (and by that any 406MHZ beacon) is different than a VHF distress System.
The PLB1 is a Satellite transmitter and the signal need to travel thousands of miles (thus 5 watts). That signal gets relayed to a Rescue Center operations in the US. That Rescue Center operations lookup your location and forwards your distress to the nearest Coast Guard, Navel, Search and Rescue in the area. They are the ones that will perform the Rescue. Your dive boat or live aboard will NOT receive your distress beacon. A Coast Guard Cutter, Navy ship or Search and rescue helicopter probably is performing the rescue.
The original Nautilus life line has a full-fledged VFH (though 1 watt) radio for voice communication PLUS the Automatic Identification System / Digital Selective Calling (AIS/DSC) distress message with GPS (ie. distress button). The new life-line has only the AIS/DSC distress with GPS. The voice and distress message is sent only to VHF Marine radios within its broadcast range. The VHF Voice realistically has about a 3 mile range to a dive boat (unless there receiving antenna is mounted high) because of Line of sight. The main limiting factor of the height of the diver antenna above water. The AIS/DSC distress on this unit realistically has about an 8-10 mile range (though they claim 34 miles). Now here is the difference in the recovery: every boat that has a VHF radio will receive the AIS/DSC message along with the your GPS coordinates. This includes YOUR dive boat or live-aboard. THEY will be probably be the ones performing the rescue. Once back on board your dive boat they will call the coast guard on channel 16 and inform them you have been rescued and no other resources will be expended. The concept here is YOUR dive boat (live aboard...) is performing the rescue (especially if they are missing a diver!). Your dive boat (or another dive boat) should well be in range of this broadcast and should be the one that picks you up.
The PLB1 is a GREAT device and provides World Wide coverage and will get you rescued, maybe even getting a helicopter ride. Down side it is not dive depth certified and needs an external case.
I just want want to get back to my dive boat.
Al