Okay booted up BG2EE for the first time last night. Holy crap. There is one huge reason to get the EEs and that is moddability. The latest SCS release for EE is fantastic. First, it allows the option for integrating spells from Icewind Dale. This isn't anything new, as other mods have done this for eons. What is new is that SCS teaches the AI to use them and use them effectively - mods like IWDification, while awesome, effectively just gave you a larger arsenal that you could use against the enemy. I don't know that this is only possible with the EE, but given that it only came about recently, it seems like it's at least much easier to do with the EE.
Bigger than that, though, is the interface changes. SCS is now directly integrated into the game itself: The in-game difficulty slider now impacts which SCS options are in use (for example, how high the slider is determines how many short-duration spells enemy mages get up for free, and when enemy mages start getting access to HLAs), and there's an in-game interface that allows you to fine-tune all the options yourself (for example, if you want high-level mages in SoA to have access to HLAs, but you don't want mages to be able to go into battle with protective spells already up).
Beyond that, the SCS Ease-of-use Party AI now replaces Beamdog's Advanced AI setting, and again, not only allows for more customization than before, but allows you to change options on the fly, instead of having to reinstall or dig into Weidu.
For the first time I'm actually excited about the BG EEs. What modders are able to do now is a lot more interesting than the already incredible stuff they were doing with the base games, and they seem to have a lot more access to things that used to be either hardcoded or just too much of a pain to work with.
Oh, also I discovered another QoL feature that I appreciate a lot - smart switching between hands. So for example you can let Minsc have a two-handed sword and a longbow and a weapon equipped in the off-hand. If you switch to a 1-handed weapon in the main hand, he'll suddenly be dual-wielding. Then switch back to a 2-handed weapon and he's not. It makes your characters feel a lot more flexible - technically it doesn't actually change anything, but digging into the inventory to swap around weapon slots every time you want your dualwielder or sword-and-boarder to use a bow can be pretty inconvenient.
It also has smart spell slots: If a caster loses spell slots for any reason (level drain, unequipping an item that grants spell slots), the game will remember what was in those slots when you gain them back. They won't be actually memorized, of course, you'll have to rest again for that. But it's actually a huge convenience. My least favourite part of fighting level-draining enemies was that if they got a couple of hits on my spellcasters, after I'd restored the level drain I'd have to spend a good five minutes retooling everyone's spell slots. This was especially an issue with SCS when you'd go up against things like the improved Shadow Dragon who could drain levels with her breath attack and dispel Negative Plane Protection.
So I'm going to say something I never thought I'd say: I recommend getting the EEs. Beamdog's new content still mostly ranges from "mediocre" to "hot garbage," but the bugs are almost entirely sorted out, the QoL improvements are real nice, and most importantly, the modding is even better than before.
DISCLAIMER: You have to use EETool to install mods for EE. EE doesn't always play well with direct WEIDU installation and BWS is no longer being supported. This is actually the reason why I only just found out about the SCS changes - I was using BWS up until last night which only had older versions of SCS, that was essentially the same mod as the one for classic versions, just ported over.