pros : lighting, even though some encounters are predictable - still made me jump in places, graphics and sound; some of the mods are good.
cons : repetitive - though environments do change nicely, at times a little clunky combat, sadly a greater technical achievment than an achievment with regard to varied game play.
For me the use of the pda was a good idea, just very few puzzles to solve where as with halflife there was more to think about than just shooting enemies. Its as if they wanted to recreate the original but mixed arcade like gameplay with modern graphics and it just doesn't quite pull it off. The amount of enemies in the original games made sense but having loads still in Doom3 just didn't work imho. Still worth a play though, defo.