You didn't mention an important point IMHO, which is the batteries are not replaceable and must be periodically charged. They claim a 100 hour life on a charge. If you're in a vehicle or only doing trips of a couple of day this is not nearly as much of a limitation as it might be with several day backpack or bike trips.
So even though Delorme has many desirable features over SPOT the question of replaceable batteries and power consumption still are important considerations when your use involves more than a couple of days away from support. The batteries in my SPOT have lasted a month doing 10 minute tracking all day with a daily check-in. So a second set of batteries is all you need to carry to be sure you're OK, assuming you plan on being in a town within the next few weeks.
It's not an insurmountable problem, carrying a power source, solar panel or something. But I think the pro/con comparison needs to mention this.
I also didn't see that the GPS and navigation really was robust enough to eliminate the need for a proper GPS device, so the size and weight are something of a negative when you consider a PLB or SPOT are smaller and lighter.
You're right in bringing up 2 issues:
1) The Inreach's batteries aren't replaceable, so you need to rely on a charging cable and some sort of power source...as you said, not a big deal for vehicle based exploration, but can become an issue for extended foot travel away from any sort of power infrastructure. I have heard of mobile device charging units that rely on solar power or heat from a fire...so perhaps there are some workarounds for this issue, though they are likely bulky.
2) 100 hr battery life does limit your abilities,
if you are using the Delorme Inreach constantly.
My take on the Inreach Explorer, and any GPS or beacon device, for camping/backpacking is that it should only be used as a backup or secondary navigation tool, not as the primary and only one. I always have a map and compass on me when I go on hikes and camping trips. I check my headings, use terrain association, and estimate my distance traveled through time passed and other pace count methods (when you spend a lot of time in the woods, some of that stuff comes naturally).
While camping or hiking, my Delorme Inreach is always off unless I need to do a quick GPS check to confirm my position, or I need to mark a waypoint or send a message out. Using the Inreach in that manner,
I've found that the Inreach's battery can last at least several weeks. YMMV depending on the weather, terrain, tree canopy, satellite link up times, ect. So I've found that Inreach has not limited my backcountry camping at all. In fact, it has encouraged me to push into more wild, less traveled terrain because I have a good safety net if things go wrong. And quite honestly, except for the SPOT device, which, while long lasting, has limited functionality, most handheld GPS devices offer similar battery life to what the Inreach offers.
How much tracking time is that? Just curious since I specifically went with SPOT because of the battery life and replaceability. I've found about 4 weeks worth of 10-minute beacons with about a dozen check-ins before they are dead. I doubt I'd jump to an InReach at this point (very happy with my SPOT and the cost was easier to tolerate) but it would be interesting.
Apples to oranges. The SPOT is a great device, but you're not getting the same degree of versatility when it comes to mapping, messaging or waypoint/routing functions that the Inreach and others offer. I don't see either as better, they just offer slightly different functions and each has their advantages and disadvantages.