I note there are non-official ISO files for installing Manjaro pre-configured for Budgie DE, however I also note it can be isntalled via SnapD…
Is there a recommended method?
IS one better than the other or is it just different ways of achieving the same end?
The ISO I have is sbk-manjaro-openbox-725-stable
… “not even wrong”
comes to mind.
It definitely is NOT one or the other of the choices you mentioned.
And?
that’s got to be one of the most cryptic replies I’ve had to a questioon!
No.
Better now?
(the rest was leading the question by narrowing the choices down)
Now wasn’t that much easier and direct? 
I don’t know.
Was it?
Did it help you?
Yes, by @Jim.B:
It seems neither myself nor @anon33601770 understands what you’re asking about.
Please help us help you by being clear and concise about the issue you’re having:
nah, sorry - imo following all that how to post, and inserting copious amounts of totally irrelevant (to the OP) information is not really required. It is a simple enough question tbh, and that greater minds than mine cannot understand it is beyond me. Of course maybe being obtuse is a permanent state on this forum?
I’m sorry, I’m having trouble understanding you. Please also show respect by using proper spelling and grammar.
I’m off to watch a movie and eat dinner. 
just curious, but are you shure that you can install a core application like a DE with snap?
Apart from that, snapcraft.io only offers themes for Budgie…
If I’m understanding your initial question, no recommended method exists for installing a Desktop Environment (DE) as a Snap package in Manjaro.
As you correctly surmised, the ISO files in question are non-official; being created independently by forum member @Jim.B (as @Yochanan has indicated above). Any queries about these ISO’s will need to be directed at their creator.
To be clear, this was unclear. If you wish to have useful responses to your questions, please ask better and well structured questions. Can you perhaps rephrase?
I should imagine what you call “copious amounts of totally irrelevant information” was given to assist you in creating a Support topic that would maximise the chances of it being understood and actionable by those who might wish to help.
A reminder that the Manjaro forum has strict rules that one agrees to by virtue of using the service; and a long memory.
Ad hominem targeting Moderation staff or other forum users and brazen disregard for forum rules is not tolerated.
The links given were indeed relevant, as are these;
Regards.
An openbox iso is a great starting point for adding GTK based desktops.
You cannot install the budgie desktop using snap. What you are offered is themes.
Yes. Install the packages from repo, those will provide you with a reasonable budge experience
$ pamac search budgie --no-aur
plymouth-theme-manjaro-fancy-budgie 1.1.r2.gca022e7-2 extra
Manjaro Plymouth theme for Budgie Desktop.
manjaro-wallpapers-by-lunix-budgie 1.1-2 extra
Manjaro Wallpapers By Lunix - Budgie
budgie-session 0.9.1-2 extra
The Budgie Desktop session handler
budgie-screensaver 5.1.0-3 extra
Screensaver for the Budgie Desktop
budgie-extras 1.8.0-1 extra
Additional Budgie Desktop components from the Ubuntu Budgie team
budgie-desktop-view 1.3-2 extra
Desktop icons implementation for the Budgie Desktop
budgie-desktop 10.9.2-3 extra
A familiar, modern desktop environment
budgie-control-center 1.4.0-2 extra
Budgie's main interface to configure various aspects of the system
budgie-backgrounds 3.0-1 extra
The default background set for the Budgie Desktop
Snap, flatpak and appimage is means to get applications on your system which are more or less self-contained.
The method they use is intended to ensure the application work as the developer intended - no matter the underlying GNU/Linux operating system.
There is trade-offs with this approach - which may vary among applications.
One trade-off is the theme where the application may blend in - but it is also possible it will not.
This is especially true if you mix toolkits Qt and GTK.
Snaps is controversial and may trigger strong opinions as it may be very resource hungry
Flatpak requires the user to be selective - because anyone can create a flatpak and publish the result - like anyone can create a PKGBUILD for AUR.
The difference is that you can examine a PKGBUILD but you cannot examine a flatpak, thus you should not blindly trust - I could say suspect the worst - but exercise due diligence.
Apply the same rule for appimage applications.
Since I was linked in I will offer one piece of advice. Never ever install system components from Snap, flatpak, or appimage. Its on for applications the worst thing that happens after an upgrade is the app stops working. If on the other hand its a system component like a desktop, audio, graphics drivers, or something like that, you may end up with a black screen and a broken system.