It does have its flaws, but Rainbow Six: Vegas is still one of the best tactical shooters available.
But alas, gameplay to the rescue. If there's one thing the game does extremely well, it has to be the sense of really being a squad leader who fights very intense, tactical battles against smart enemies. Key here is an elaborate cover mechanic that lets you hide behind pretty much any flat surface or small object. When taking cover, the camera will pop out of your head and switch into a 3rd person over the shoulder perspective, that lets you look around, aim at enemies and quickly jump out of your cover for a few well-placed shots before vanishing behind it again. It's a great system and necessary as well, because the A.I is pretty smart and you can only take a few hits before your vision goes black and you drop down dead if you don't recover for a few seconds.
The level design is all over the place though as some passages are very linear in an artificial way like lines of cars stacked behind each other to form barricades, while others offer a variety of options like roping through windows or multiple entrances to surprise the enemy while they are distracted by your teammates. On the other hand, the Vegas setting is for the most part really nice and certainly hasn't been done before in this fashion in any other game. Since the game relies on checkpoints to save your progress, it's note-worthy that their placement is quite fair and tries to eliminate some of the frustration that can occur during a few especially challenging sequences.
From a technical standpoint, the game is solid, falls victim to a lot of nagging flaws however. While the sound effects, especially the realistic weapon sounds as well as the solid voice cast, are excellent, the mixing screws up at times, making gun fights in the room next door sound like a mile off and some character voices are almost impossible to understand even if the talky heads are right next to you.
Same for the graphics which are certainly solid and run at a smooth frame rate for the most part, but oddities like a few muddy textures and pop-ups like weapons disappearing and re-appearing as you move a few feet away give the game an unfinished feel. In addition, the game's 1080i support is basically busted which adds to that impression, although it runs fine in SD and 720p.
Rainbow Six: Vegas's multi player component is fantastic though as the game sports 2-player split screen, LAN support and online play via the PlayStation Network for up to 14 players with a total of 10 game modes on 20 maps. Modes include variations of deathmatch and team deathmatch as well as a capture the flag-like mode or escort missions where on team has to guard a VIP while the other team has to eliminate that person. As with all online play though, your mileage may vary and some players, including me, have had some issues with the game crashing at times. If you get a game going though, it's extremely fun and rewarding, as you'll gain experience, rank up and are given access to new weapons and equipment.
All in all, Rainbow Six: Vegas is a great game, especially in multi-player, but has some issues like a few bugs and a rather disappointing story line. Still, it's easily one of the best tactical shooters to date, especially on the PS3.