GameBanshee Forums

Can anyone tell me why you would use "shadow door" over "invisibility"?

Actually you should compare it with the improved invisibility. Then it turns out that you cast it faster and thus is better to get out of combat. Other then that I don't see anything better.

Improved Invisibility doesn't just help you get out of combat, it aids you before and during. If a character is under Improved Invisibility it generally gives them an advantage in gaining the first strike. In the case of mages, this is especially handy when they cast area of effect spells since it gives them a head start.
Also, Improved Invisibility grants a bonus to AC, and unless it is dispelled by something like True Sight, characters that can't be seen can't be targeted with spells.

I use it as part of my buffing repertoire all the time.

I'd select it any day over Shadow Door, but that always depends on play style.

In Icewind dale II improved invisibility is very useful. It protects by 50% when attacked by melee. So, from 2 attacks that would hit you, only one will do. Is it the same in BG2?