I'm a bit late to the party but thought I'd offer you my advice and hope that it's a little helpful, and sorry it's a bit of a wall of text.
My Switch is on 5.1.0, I wanted to keep as low as possible to preserve my Fuses yet still wanted to do the most I could so I stayed at that firmware hoping that EmuNAND would be released. I also wanted to be able to play online if I could but that wasn't a priority for me so when the ban waves started I took the precautions of deleting WiFi settings and so forth. I wanted to play my backups and also in the first days SX OS was apparently the safest (most bans those days seemed to be related to LayeredFS) so that was the Option I went with. I have been happy with it as a complete setup and the fact it plays my backups, I also setup a (Separate Partition) EmuNAND when it was released and updated it offline using ChoiDojourDX.
How this might help you:
My setup is
SysNAND - 5.1.0 (fuses 5.1.0)
EmuNAND - 6.2 (fuses 5.1.0)
AutoRCM - Off
I leave my switch is sleep mode most days however when I turn it off depending on what I want I do have to boot using my "Jig" (paperclip + Phone, still waiting on Dragon Injector
). if I boot using my Jig it will auto-boot the EmuNAND (you can bring up the menu if you hold + as it boots) , if I boot without RCM/Jig it will boot my SysNAND on 5.1.0. I've only had the battery drain on me once while was traveling, I just plugged it in and it charged up then booted SysNAND, I wanted a bit then rebooted into EmuNAND and happy off I went. I like the EmuNAND it protects the SysNAND from update's, bad NSP's (should still backup often) and means you can make as much of a mess on it and it doesn't affect the SysNAND, you can also have a "proper one" to play games on and a "dirty" one to test homebrew and such on.
I won't be super Pro or super Negative against SX OS as some people on this forum are, I found I have pro's and con's from it, pros are definitely EmuNAND and Being able to play my own Backups, it's a simple setup too. negatives is you can't customize it (load personal Kips etc) and your stuck waiting on updates sometimes. You say you have the SX Gear so it's definitely handier for you to load it up, it can use NSP's and while not caring about a ban it does have stealth mode which it kinda handy as you can play online using
Lan-Play without worrying about DNS with is handy.
AS for other Custom Firmware's they can do mostly the same, some setup are harder, some easier but you can match them a lot more to what you want. also Atmosphere does seem to be updated a little quicker when it comes to Nintendo's update Shenanigans but if I recall it doesn't support SigPatches (without some modification but I don't know much about them so I can't really say and you only really mentioned SX OS.
Hope it helps you with your decision ^^,
