The device is pretty cool, and once you get it set up and connect to your phone with BLUETOOTH, it is pretty simple to send a message.
The app on your phone has a message link and you can choose a recipient from your contacts. Shows your text message overlaid on your map location. Cool...

But...

Getting it set up can be a challenge. Garmin's website offers multiple videos that tell you how simple it is to set up. But that's the end of the simple part. No where on their page are there any actual instructions or directions. No Clickable link that jumps out at "NEW USER".
No numbered steps. I've been at this for 3 hours now. I'd say I'm as tech savvy as the average 62 year old guy.
The web site needs help
And their tech support shuts down Friday at 7:00PM central time
Great help for equipment designed for weekends.

And the pre-set messages that they mention prominently in their videos? Confusing and difficult to set up. I tried to set it up for the pre-set message to go to my wife, but it defaults to the user's email and goes only there.
So... As it stands now I can only use pre-set messages to message myself via email.

And it seems as if the pre-set message was only designed to be used once. I cannot repeat it or re-use it.

The pre-set messages are supposed to be unlimited and no charge as long as you have an active plan.

The messages you send via phone are all paid messages, and it you go over your limit it's $.50 ea...

In a nutshell, I seem to have a communication device that works only with my phone connected via bluetooth. The free and unlimited pre-set message feature is confusing and difficult.
No doubt that 10 minutes on the phone with a tech rep will solve all difficulties, but no one is gonna answer the phone til Monday.

FWIW the pre-set message set up page has an FAQ link And an Operator Manual link

Both are inoperative

I've had mine for over a year now, the biggest drawback is the lag time it takes to send and receive messages....oft times 15 minutes before it sends then another 15 minutes to hear the reply. They are not instantaneous like texting on a phone. They remind me of the first GPS devises commercially available to the public that took 30 minutes of wait time before it could get a fix on your location (and with only 5 hours of battery time on those early devises you better walk fast). I suspect that eventually things will speed up, but in the meantime they require patience to operate.

Cell phone texting is improving where I live, and most of the time now normal texts get where they're going almost instantly. Still, delays do happen, and it's not unusual to get a text that someone sent hours or a day ago.

My experience with the satellite messages last night was that they were received in around 30 seconds or so. I have no doubt that delays can and will happen.

Depends on your settings. The unit will look for new messages every 15 minutes. But if you manually ask it to look or send another message it will be quicker.

I can pretty much text my wife with a few minute replies when on ocean. It’s really fast. Once you get in the woods it’s much slower.

I’m going on 4 months with mine and it has grown on me. It’s not intuitive to use but when you get used to it, it does what it’s meant to do, especially when paired with a phone. Stand alone it is cumbersome. I wouldn’t want to carry on a long conversation, but as an emergency beacon, back-up gps, and a way to check in a couple times a day it serves its purpose well. Especially given its size and weight.

Do you guys have issues with the mini losing sink?

The 66i is constantly losing sink with my phone. I have to delete both and start over.

Drove to Iowa's Yellow River State forest this afternoon and fished for a few hours. This is cell phone free Iowa, and no one ever gets a signal in this area.

Messaging my wife and son, using a linked phone was easy. Not sure how it happened but one message from my wife showed on my main phone screen, but never did appear in the app.

Fishing was crowded and slow. I thought that maybe this late in the season there'd be fewer people out, but the great weather seemed to have about everyone with a fishing rod up and at them.

I got one small rainbow on Big Paint creek, and a rainbow and a brown on Little Paint.

Young couple from Colorado was wading/fly fishing Big Paint. The gal had 6 or 7 hook-ups in about 10 minutes.

I'm exchanging texts with someone out in the bush. She is using in reach and it sometimes takes days for me to receive a message.

Or maybe I need to check them more often.

Was a little funny...
As mentioned above, yesterday's test was in a portion of Iowa that is notoriously absent of cell phone coverage. Being a Saturday afternoon, there were a fair number of folks out.
I was sitting on a bench in Little Paint campground messaging my youngest son. Young guy setting up his rod nearby sees me with my phone. Sets his rod down, pulls his phone out and walks a circle looking for a signal.