The First Rainbow Six game I Ever Liked
First, graphically, this game is phenomenal. Vegas is such a terrific locale for a game like this and this game is legitimately beautiful. The "training" levels in Mexico are fun --- but the game goes through the roof when you finally make it to Vegas. Casinos are one of the all-time inspired locations for squad based combat as there is never a lack of hiding places and cover to launch attacks and counter-attacks. If you are too aggressive, you can walk right into a shooting gallery where the enemies will chew you up, but occasionally, attacking before the enemy manages to dig itself into position is the wiser action.
Your squadmates tend to make too many dumb choices for my tastes, but they are vital to your survival and will do a lot to help you survive. The enemies are hardly dumb as you will have several laying fire on you to allow their teammates try and flank you. The enemies that drop in via skylights tend to be easy targets for a slaughter, but that is the only noticeable problem with A.I routines. Enemies and teammates yelling out orders is all the more immersive.
Even if you've never liked R6, such as I didn't, you should give Vegas a shot. You will not regret it and you will play one of the toughest, but most playable, titles released in a long while.