I used a SPOT Connect (discontinued model, used a smartphone as user interface) for about three years, or should I say tried to use. My wife was not interested in looking at a track on a web page so I sent messages periodically (which were prewritten and selected on the phone, or typed and sent). This product had a great concept but the software and hardware were not up to the task. Often I got home and found out the messages were not received. I now think I should have had tracking running all the time even though I was not using it. The redundancy of SPOT's 10 minute tracking helps minimize the likelihood of a bad location or failed transmission. I found that I had to be stationary with excellent sky view and wait for several minutes, e.g., stopped on a summit or there was a high probability that either the GPS position or satellite transmission would fail (either prevents a successful message).
Five weeks ago I got a inReach SE and I am really impressed. It works so much better. A very important feature is a "whistle" reply from the satellite that the message was received. On a summit the reply is in a few seconds before I even put the device back in its holder. Other times it may be a minute or two, but unlike SPOT it gets through. Delorme mentions redundancy in sending if the inReach doesn't get the reply (but don't say what the interval or retry attempts are). The tracking feature also works very well with almost no lost time intervals (by viewing the exported tracklog in a track editor program, such as Garmin's Mapsource or Basecamp). I have also overlaid the tracks with simultaneously-acquired handheld Garmin tracklogs. They are as closely similar as could be expected for consumer devices, certainly close enough for a rescuer to find you easily.
Winter temperature and battery power are not a problem (mounted on a pack strap) even below zero F, but of course the phone needs to be kept close to the body or it will shut down. Inreach has three prewritten messages synced to the device which are quick and easy to send with minimal gloves-off time. I only write a custom message with the phone infrequently, but it does work (if the phone doesn't shut down). I agree that the selection rocker is touchy and doesn't always go in the desired direction. This should be an easy fix.
Overall, as a former SPOT Connect user I am completely satisfied with inReach SE. The web viewing and user control sites are excellent, unlike the clunky software operated (and never improved) by SPOT for years. Technologically, SPOT is years behind at this point and haven't introduced a new product since SPOT 3 in what, three years? They are just milking the high-margin subscription service while they can.