The graphics themselves are a bit outdated by modern standards, the games use sprites rather than models. The aesthetics however hold up and are top tier still. Story, music, atmosphere etc is all worth it in my opinion.
The game mechanics are a bit aged but... I think it is closer to 5e than 3rd edition is to 5e. The mechanics do hold up still, I think. Sure, it is not as good as what we have now but once you get used to it, it does work for a CRPG.
The first game is based around story buildup and exploration, small side quests and more humour (almost the sort of thing you can expect in Divinity: Original Sin games) and there are fun little easter eggs. BG2 becomes more storyfocussed, and somewhat more linear, though with plenty of sidequests still (Some short and sweet, others involving longer stories and their own seperate areas with dungeons).
I would say check out some videos with gameplay really. If you can get past the graphics themselves, and the 2d style with sprites, the story, aesthetics, adventure-experience etc makes all up for that and I would definatly recommend.
