The only problem I remember having was bad performance on multi-core processors.
Solution: Change the Divine Divinity process affinity setting, so it only utilizes one core.
Might be a bit tedious to manually have to change affinity each time the process is created but I'm sure there are software out there that can do this automatically.

First, the GOG version of the game lacks the changes listed for the new digital release (these changes existed briefly in the first GOG release, but were removed b/c of a mistake). These missing changes are:

General:
- Fixed numerous crashes and freezes
- Fixed: encumbrance could make items disappear
- Feature: Tooltips of damage stats on stat screen improved

Skills:
- Fixed: Spellbooks no longer ignore level requirements
- Fixed: All weapon expertise skills give percentile bonuses instead of static bonuses
- Fixed: True Sight damage is now actually used
- Fixed: Bow and crossbow expertise bonuses are now actually used
- Fixed: Divine Eye removes the fog of war
- Fixed: Deadly Gift's Scorpion Trap is less powerful
- Fixed: Resurrected enemies die after region swap

Furthermore, because the wrong masters were used to create version 1.005, patch changes from years past are also missing. These possible missing fixes are:

Bugfixes addressed in V1.34

Bugfixes addressed in V1.33

Feature changes/bugfixes introduced in V1.32

Feature changes/bugfixes introduced in V1.31

It is true that GOG was not created based on the latest code, but I don't think it's that bad that all fixes from v1.31 and onwards are not in there. We are going to look into this next week.

thank you bengeddes, I was going to play my gog version, but now I'll just wait and play something else instead, I hope Larian fixes this one up, or no Dragon Commander at day one for me. I got a giant back catalog both here and on steam, so I'll just keep playing something else

Well, this sucks... does it make this version pretty much not worth playing?

I played the original disk release (1.0029A), and didn't run into any serious bugs (and few minor). I was half way through before installing the 1.32 patch.

If you have other games to play, then you may want to hold off and see if or how soon a patch may be released. If you want to play this, then do so.

Just quickly tested some of the above fixes bengeddes says are not in the GOG version, and GOG is at least at 1.32 (e.g. screenshots are in png and there is an error.txt file)

Even looks like a lot of the 1.33 fixes are in. I cannot vouch for all the 1.33 fixes cause I can't reach them that quickly, or reproduce them, but it would be weird if only a handful of 1.33 fixes were in.

For instance, I haven't seen the following bugs:
- Fixed:Scene hangs in Ionas dungeon when Arhu shows equipment
- Fixed:Council of Seven Scrying scene problems
- Fixed:Trevor dialog, can expose Tingalf before receiving quest
- Fixed:Scenes hanging around Aleroth
- Fixed:Cannot tell Mardaneus you found Georges murderer in the COS
- Fixed:Vampire in cave problem with immortal status during scene
- Fixed:George killed monologue always plays when entering georges house
- Fix for trolls being already dead when arriving at bridge and the guards being mad for not helping them while the player never saw them before

You can drink the bottle of ale Rob asks you to retrieve as a lockpicking test to join the thieves guild, and still join (1.33 fix).
Initially there is no chest in Malcolm's house in Verdistis, fixing the disk version issue of the house being sealed when you purchase it, and that chest being reset (potentially loosing any items you placed there earlier).
Finnigan's magic lockpicks are unbreakable (1.32 fix), but disappear if dropped on the ground (like in the disk version with a patched game in a save started with the original release 1.0029A). So that's a partial fix; in a game started in an updated disk version, the lockpicks are unbreakable and can be dropped on the ground (though given their benefits, there is little incentive to ever remove them from your inventory).
I was unable to join the merchant's guild by paying gold (1.33 fix), though that isn't the best way to solve that quest anyway.

etc...

Uh guys, I am currently playing it, I have zero problem, it's become one of my favorite games.

Ah yes, I had one bug. The game wouldn't let me save after a cutscene accident, in a cemetary cave. I had to reload a former save, and the bug didn't re-happen. So yes, I've had 1 problem.

But that's all, and I'm quite far into it. And I can also confirm that one famous bug that is supposed to make one skill useless (ranged weapon damage inscrease) is corrected in the GoG version.

nice to know, still not happy that steam has a better version GOG staff should ask Larian to keep their product to the latest release

Telika;

That wasn't a bug. The cutscene at the start of the cemetery cave is connected to the one at the end, so saving is disabled between the two (it is a smallish area, though).


Eclipse;

Larian is already checking if the Steam version can be released on GOG (which would make any future updates easier). I've been doing stuff in both versions, and other than the Steam version having a slightly better configuration program and dropping support for Win98, I'm not really seeing any difference between them.

I think it was a bug : i got an error message (in a pop-up window) about a corrupted save and an interrupted cutscene, and if i remember well, ending this mission dodn't restore the saving ability that time. When I retried it, i just got the normal temporarily disabled save function.

In that case, then, it was a bug.

Alright I edited my post to state these were possible missing fixes from older patches, since right now it seems like a grab-bag of random ones that are applied.

Take the word of someone who has tested these bugs over my word - though it's been verified that there are at least some outdated files and missing fixes. I listed the entirety of the patch history for completion.