Well speaking as someone who purchased the game from GOG and fell afoul of both these bugs, it would have been nice to a) Known about them before I ran into them, and b) had them fixed in a patch before releasing it to GOG. Having said that, the workarounds are easy, once you are aware of them, and the game is great.
I've purchased both Divine Divinity (DD) and Beyond Divinity (BD) via GOG.
My system is Core I5 based (quad core), Windows 7 64 Bit.
DD runs really well and the config tool even allows me to select the correct resolution (widescreen) for my monitor.
BD runs well enough, but for the Inventory Bug, which renders the game unplayable.
It's also dissappointing that as a later game (than DD) that widescreen support has not been rectified in BD.
With regard to the BD inventory problems, I've not been able to get the game to run in any of the compatibility modes other people have had success with, notably Nt 4.0 SP5 or Win 98/ME.
Shame really, it would have been great if Larian had put as much effort in preparing Beyond Divinity for release via GOG as they did Divine Divinity.