One No would do, because I just disagree more when repeated.
Sorry. I was worried about you.
I would rather have a Delorme than a VHF in a liferaft, which was the confine of the comparison. This did not presume one even has an EPIRB, it's just the sole comparison of the two.
If you are offshore you should have an EPIRB (part of GMDSS). Satellite messengers like the DeLorme are not part of GMDSS - they aren't life safety devices.
Let's consider two scenarios:
1. GMDSS. Something bad happens to your boat (flood/fire/collision/a splinter in your finger/whatever). You trigger the EPIRB by flipping one lever. The signal goes to a satellite that captures your exact position and forwards the emergency to the USCG Mission Control Center. Based on position it is immediately forwarded to the cognizant Rescue Coordination Center (RCC). The watch officer gets the alarm and people start moving. They call your emergency point of contact in parallel with alerting SAR resources. 5 minutes. Meanwhile you launch and inflate the life raft. Confirm that it is time to get off the boat. Move everyone and your ditch bag and your childhood teddy bear into the life raft. The light on the EPIRB blinks reassuringly but you still have an overwhelming desire to DO SOMETHING. You pull your little solar panel out and tie it to the life raft canopy and run the wire to your VHF. The sea anchor holds you steady and the water bags fill. It still isn't any fun in there. In a couple of hours the VHF crackles to life as fixed wing SAR overflies and the USCG checks on health and welfare of all aboard. They fill you in on the recovery plan. Three hours later a USCG helicopter that refueled on a Navy amphibious assault ship that had diverted to a rendezvous circles. The VHF crackles to life again and the USCG fills you in. They drop a swimmer who joins you in the life raft. There is now water everywhere. *grin* One by one they move you into the water and the recovery basket (life jackets, yadda yadda yadda).
2. Consumer stuff. Something bad happens to your boat (flood/fire/collision/a splinter in your finger/whatever). You find your smartphone and your InReach and text someone ashore that you are in trouble. Launch and inflate the life raft. Confirm that it is time to get off the boat. Move everyone and your ditch bag and your childhood teddy bear into the life raft. The signal strength bars on the InReach looks good. You send another text message that you have abandoned ship and really need help. Meanwhile ashore your point of contact has been in the grocery store. He sees your message when he gets to the car (you just lost 45 minutes). He looks up and calls the local USCG phone number. Coast Guard Station Wherever answers the phone and has to look up the procedure because boats in trouble offshore are not in their job jar. He calls the appropriate RCC (unless he doesn't in which case after getting your position which was read to them over the phone by someone who read it to them over the phone (remember the telephone game) they transfer the call). Lots of reading and questions and repeats. Realistically figure 30 minutes to an hour. They are still going to run through some confirmation that the call is valid. More time lost finding emergency contact information. SAR resources start moving but another 10-15 minutes to validate the call. Meanwhile you pull your little solar panel out and tie it to the life raft canopy and run the wire to your phone to charge it and then your InReach; at least it gives you something to do. The sea anchor holds you steady and the water bags fill. It still isn't any fun in there. In a couple of hours a fixed wing plane overflies. Did they see you? Are they even looking? Eventually (one to two hours - they have other things to do to save you) you get a text message from the RCC after they hear back from the deployed assets. Three hours after the airplane overflew a USCG helicopter that refueled on a Navy amphibious assault ship that had diverted to a rendezvous circles. They drop a swimmer who joins you in the life raft. There is now water everywhere. *grin* They have no idea what is going on and you don't know what the procedure will be. An extra fifteen minutes to get everyone on the same page. One by one they move you into the water and the recovery basket (life jackets, yadda yadda yadda).
In the end, using a satellite messenger will take anywhere from an hour to four hours longer to get you help. Again, all it's really good for is morale. That's why they are priority 4 on my list.
We haven't even talked about drowning your phone (Lifeproof case? oops - you were charging) or the InReach (not nearly as waterproof as they seem). We haven't talked about queueing the SMS in the satellite constellation. We haven't talked about all kinds of failure modes of something not designed for life safety.
Feeling good about the SOS button? That goes to a control center that still isn't part of the GMDSS. There is no latency specification for that message. It rides on the tertiary control circuit and is last in line through the satellite constellation. To my knowledge the connection from Iridium (for the InReach) and Globalstar (for the SPOT) to USCG is still by phone into the MCC where someone has to type it into the system (did they get all the numbers right? more time repeating three times) before it launches. They still have to validate the call which means more phone calls to get the data and then follow up.
it's affirmative confirmation of distress
It isn't. It is a single distress call which SAR will attempt to confirm. The process is that SAR starts to move on receipt. The reality is in-system (GMDSS) is more credible (it shows up on the computer screen) than some voice on the phone.
its batteries are likely to far outlast the VHF, which you indirectly acknowledged.
Until you start sending tons of text messages because you can. Do you have the discipline to leave it alone?
VHF needs to be in range of someone to hear it.
That's what it's for - short range comms. Fixed wing SAR, helicopter SAR, commercial, USCG, military ships that heave over the horizon looking for you.
Triggering an EPIRB does not immediately launch rescue assets. As I understand it, they first use the database contact info to attempt to determine the validity of the alarm. I've even heard ch16 broadcasts, asking vessels in the area, if they can sight the distress.
It takes time to get on-duty people from the ready room to aircraft and the planes in the air. It takes time to work out refueling plans. It takes time to identify any AMVER assets in the area. Validation happens in parallel. Will they possibly hold up some expensive assets waiting for confirmation? Maybe. A text message from a satellite messenger is no more and possibly less credible than an EPIRB.
The DeLorme has an SOS button and you can describe the problem. They have 24/7 resources waiting to coordinate.
That is a big benefit for hikers and such that don't have a global distress system like GMDSS. It is second tier for cruisers.
The device will advise SAR as to whether they should respond with a 90 min cutter or 10 min helo, if not help them make a decision to send anyone right away at all.
If you are that close you are in range of VHF on Rescue 21.
Personally, I have an EPIRB, DeLorme, cell phone, SSB w/distress and multiple VHF w/distress, including a dedicated one in the ditch bag. I wasn't advising to only have a DeLorme.
I stand by my list of priorities. #1 EPRIB (or PLB if you don't venture far offshore). #2 Handheld VHF. #3 Extra power for VHF (replaceable batteries and/or solar panel). #4 morale support with sat phone or satellite messenger.