I just want to focus on those two.
I'm an 11 year SPOT user - all 3 generations of messengers. I've hiked, fished and hunted all over Oregon and Idaho. I'm older now, family is raised, wife is still with me after 38 years and grandkids think I'm fun. I have no idea how many multi-day trips I've taken into wildernesses, but I've been "off grid" a lot and I frequently goof off in places with no cell service. Highly likely that I will "upgrade" to either InReach or SPOTX next year after my special service plan expires.
One of the things I've learned is that for me, probably because I'm special, Spot has been rock-solid reliable. I have tested the system more than most, and I'll gladly link to a bunch of YouTube videos showing how I did it and the results. So to say something like "the InReach flat out performs the Spot system" isn't gonna fly - I'm not some ignorant noob. Anybody can make unsupported statements like "Glock voids your warranty if you shoot cast bullets" - but saying it doesn't make it so.
Probably the most interesting thing I learned about providing loved ones with tracking/status info is that
they never use it. Nobody ever opens the link I've added to look me up on the map. Nobody checks the tracking.
What they want is the comfort of knowing I'm OK - and it is a very big deal to them. Only once did my family get nervous, and that was when I sent them a custom message saying I was OK, but running late. My son, (avid backpacker/hunter/fisher), in Idaho pulled up the webpage to check my track progress and then called my wife to reassure her that "he's on the wrong trail taking a weird way back so he's gonna be late. He's making progress so he's OK". Neither my wife or daughters had ever looked at the track info before - even though I made it a no-brainer. But I catch hell if I go somewhere and forget to take my SPOT.
So if I look at my average texting a day - probably less than 10 texts a day. When I'm on some lake with a grandkid, all folks want to know is that we're OK. Since my adventures are slightly higher risk (weather and isolation) my family is more concerned about my safety than getting ahold of me.
Because of all this, for me 2-way is a "nice to have", not a necessity.
SPOT, InReach and PLB Info