Do not try to communicate with any type of chopper with anything except degrees and decimal degrees.
Thank you, I didn't know that.
Now back to the original question – SPOT or the like or a PLB? You get to choose where to place your trust.
Understanding that I have no background in SAR and have never owned a PLB or SEND, I still have an opinion :-).
For best reliability, I would carry a PLB. I think that the communications systems it uses and the back-end processes are time-tested and resilient. It also seems that the devices are more rugged and likely to work when you need them. A PLB is by far the least expensive option over a five year span.
For best flexibility, I would carry a Delorme InReach. It's got great coverage and with two-way messaging could be very helpful in launching a rescue that's appropriate to the emergency, or launching no rescue at all if a group is overdue but not otherwise in distress.
The SPOT and SPOT Connect seems most useful to me if you are comfortable with one-way communication and more limited coverage than a PLB or an InReach. The SPOT Connect in particular is useful for launching an appropriate rescue or no rescue at all.
Here are the lowest prices I found. Costs go up significantly for the InReach and the SPOT Connect if you don't already have a compatible device.
ResQLink: $233. Five year cost: $233.
InReach (assuming you have a compatible device): $250 + $9.95/mo for the Safety plan. Five year cost: $847
SPOT Connect (assuming you have a compatible device): $150 + $100/yr. Five year cost: $650.
SPOT: $100 + $100/yr. Five year cost: $600.