The OpenXcom AI should be 99.5% identical to original AI.
OXCE+ AI has some optional features you can enable:
1/ "leeroy jenkins" mode... to blindly charge... if you wanted to pump up zombies, chryssalids, etc.
2/ "spotter/sniper" mode... to allow AI to shoot beyond visible range (just like player can)
3/ and a few more small things, like better short range weapon usage, better multiple weapon usage, not reacting with very small chance to hit and such... all configurable and turned off by default