My future of sailfish worry is volte*. Looks like all US carriers are dropping 3g in the near future, so voice is gonna have to go all packet switched whether SFOS is ready or not. UBPorts seems to be facing the same future with no solution in the works. Don't want to stop using SFOS. I'd probably get passive aggressive and get a flip phone in that case . . .

OTOH, loving how much more reliable VPN is in SFOS 4. Hasn't been dropping connection then forgetting passwords. It's a monster dexterity PITA to get into the password manager while the VPN password dialog has screen focus. Also interested in the multi-user possibilities.

*Also, how do people pronounce that? Voltay? Voltuh? "Volt" as in one Amp times one Ohm? Voltee, like the Italian volti subito that I write on particularly nasty page turns in music?

Different devices I guess, and different customisations. I have XA2 with latest SFOS release running smoothly without major issues, I gave up on GPS long time now, but that's not a SFOS problem, it seems like an AOSP issue for the XA2.

I'm not saying you don't have a point, but:
most of these issues could be hardware/firmware specific or even dependent on outside factors, and there's no solid way of testing/comparing it (other than re-flashing the original Android OS, which might be impossible at this point).
In my experience, the hardware of XA2 isn't the best - even having another XA2 device (with Android) to compare with wouldn't give scientifically valid results because the hardware degradation would be inconsistent.

I go by VoLTE -> Vo-L-T-E.

Agree on the matter. Walled garden is the wrong term imo but there are shared symptoms.
The cause is very different tho. We have no elitist payed guys "sitting" on their knowledge, only releasing it for rolling bucks.
The cause for info about the Pro¹ port being scattered or only available on request is because no one (but the porters actually on gitlab) keep documentation up to date and cares to announce changes.

That, looking at myself, is just because no one cares to document (or publically blog) for such tiny userbase.
Heck, when i reflashed last week i followed 3 different blogs before realizing they are all outdated (youngest only 3 month old) and flashing the port nowadays is as simple as get fastboot to work and execute a flash.sh.
Next realization, i am the first to even flash the 4.0.1 build from then 7 days ago and did not expect it to be non-operational at all. Leading to yet some hours more noobishly trying to figure basic stuff out.
From that i learned yet again, in such a tiny community just ask at the source.

And that is not at all Discord centric in Pro¹ case. There we just have a user party trying to help each other out in "zero level support" fashion to not bug the porters with minor stuff.
The porters them self are available on Telegram and answer to everything within a day from my experience.
https://t.me/sfos_user_pro1

I think 'walled garden' is the perfect description. There are promises of all the wonders within, but you can't find out whats really there without paying the price of admission (sign up / install their software platform / whatever). You can't peer in from outside (anonymous viewing), and you can't check a catalogue (i.e. the contents are not indexed by outside search engine as far as I can tell). And as such, if/when the head groundskeeper decides to change the price of admission, or demolish the whole place and build a carpark, any content is likely lost.

Yes, I'm old and grumpy. Sorry.

As robthebold said, VoLTE seems the biggest single risk to SFOS future. My biggest annoyance with SFOS is that after 7(?) years and 5 handsets, I've still never acheived a reliably working telephone. I get random call drops, lost audio, randomly forgotten or ignored bluetooth headsets. There are other issues, but over the last year, working from home more than ever, has made me realise how annoying it really is. Working for myself, there's only so many dropped or missed customer calls I can take before it stops being funny.
I have seriously considered a dumb 4g phone several times, but I don't think I could stand sending SMS that way in the 21st century

Sold my XA2 and got a OnePlus One with Ubuntu on it. It is a different but nice experiance. Still playing with Sailfish on Jolla 1, Aquafish and Aigo X86.