SPOT / PLB Izogi and madpom have summarised the differences nicely. There are pros and cons either way, which is "better" depends on what you're looking for. For me, an older guy often tramping solo, SPOT wins. Main reason? I leave a trail, so that even if I can't activate the SOS feature due to incapacity or location, family following me can see I've stopped when I should be moving, and provide accurate information to the authorities as to my location should I not be proceeding as planned. SPOT's transmission signal is weaker, but that's generally not an issue. Later versions (SPOTs 2 & 3) resend track points so if one track position is missed it will likely be picked up on the second or third transmission. If I was stuck in a gorge with limited sky view would there be any advantage of one over the other. I don't know because we're not allowed to do this sort of comparison. But with SPOT you'd have a good idea of where to look.
So to lupin who is seeking advice, I'd say first figure out what you want, then do the pro & cons exercise. There is no PERFECT solution.
i'v had the latest generation spot fail to update my location for almost an entire day because i was under tree canopy so i wouldnt say its that reliable in showing people where to look. i ended up tens of kilometres away from my last known location,
I`d go for inreach over spot any day. The Iridium satellite constellation provides global coverage including polar orbits so faces none of the limitations of spot - there will be satellites in all directions from any location so any view of sky will work - eventually. inreach is also 2-way so confirms that your message has been delivered - so you know where you stand. Spot is send and pray -no way of knowing if a message / trackpoint / sos has been received.
Plb is still the likliest to get an sos through, but if you want tracking and messaging take a serious look at inreach before going with spot.
with good satellite coverage you only need a small gap in the canopy or a thin canopy and you should get a satellite connection, with bad satellite coverage you need a large gap in the canopy to have a chance to get a satellite connection and you have to wait in that gap a lot longer for a satellite to pass overhead to get the coverage make the connection...
I've had the McMurdon fastfind for 7 years or so.
got the Inreach a year ago, and have used it quite a bit (not in emergencies)
I carry both
the Inrech is good for getting forecasts, notifying of delays in finishing trips, arranging picups. But getting messages out can be delayed for a while, usually about 15 minutes sometimes more, in valleys. On the tops its a lot quicker
But if I am badly injured, I want to get help immediately, and don't want to rely on the variable satelite reception of Inreach. So that's why I have the PLB as well.
If had to choose, one or other, I'd pick the PLB.
But Inreach has made trips into the hills much more simple
Has anyone local tried a YellowBrick device, which now seems to be called an unpronounceable YB3? https://www.ybtracking.com/products-yb3
I've seen occasional sporadic reports around the web that some people think they're more reliable than SPOT, but not much else. From the website and logo there's apparently lots of focus on yachting, but it nevertheless is a handheld thing.
yellow bricks use iridium satellites, same as inreach, but inreach also use the global star satellites as well.
SPOTs dont use iridium, they just use global star which have less global coverave than iridium