Fancy seeing Reonaut here.

Similar to reoville, there are tons of useful info all over the place. Also lots of friendly people who will help you.
Grand is built for certain usage pattern. Grand for 18650 and Mini for 18490. Anodized finish is tough and there really isn't much to do on it except to learn how to squank.

Even cleaning is as simple as putting it under running water and brush a little. It is great for every day usage and can take a beating. It is a great mod.
On the other hand, Just GG is almost polar opposite. It is a beautiful mod and you can't help but to keep it nice and shiny. There are many threads on polishing and maintaining GG. Bish (he is like super x in reoville) has several videos on cleaning. This is totally optional but most of are drawn to it since the mod is.. beautiful.

Also since it is modular, you can try using in different configurations. 18650, 18490, +kick, Stealth.. etc. Very versatile and plenty options to keep it interesting. The options increase 10 fold when you start to combine various atomizer options. Even with Ithaka, you can run it Nr or R, Long/Short, Clear tank/Steal.. etc. Also, Ody, Pen.. etc. Not to mention the options available when you put on the 510 base.
Reo's mod is something you buy a mod (or two), add juice, and vape. In the case GG mods, you can spend hours or weeks trying out different configurations and tweaking here and there. It is a science on its own. This is why lots of discussions here are more on the mod and less on social topic.
Two main things that might be useful.
Atomizer (ex Ithaka) is much more sophisticated than simple BF atomizer (ex. RM2 or Chalice). Proper wicking is critical and very different from 1/2" short wick on BF atomizer. Similar to learning how to squank, take your time and you will get it.
There are many parts to deal with and you will become comfortable disassembling/assembling these parts frequently. This is very different user experience and needs different expectation/mindset.
I am not sure if I am making ANY sense with this late night writing,

but just remember that, similar to reoville, there are lots of very friendly people here (including the modder himself) who will definitely help you.
Welcome!