I've been playing L4D2 on PC since it came out, although my free time sucks. I finished the first two campaigns though. If you loved L4D you will really love L4D2. If you felt L4D was lacking content or was too repetitive I recommend you give L4D2 a try. The events in the game aren't really "wait for rescue in this closet while you kill hoards of zombies" any more. The scenarios are much more complicated & fun this time around. Take for example one of the parts where you are in a mall & you have to collect the gas tanks spread out every where while fighting off a never-ending wave of zombies. Tanks come out ever 5 minutes or so, too. The gas tanks are spread out over 3 floors of this section of the mall. Your best bet is to either move as a team, or split up in pairs. One goes to the second floor, one to the third, and you just basically pick up a gas tank & chuck it down to the first floor. Then when you go back down, pick up the tanks & start filling up the car to escape. I really enjoyed it. The only time I completed it I had my entire team watching my back as I gassed the car up. Someone got pulled away from the group & dropped to the ground. Then a tank spawned and beat someone else down. I had two more gas tanks to use when the third guy was dropped & the tank came for me. I managed to gas the car up & get the hell out within a second or two of death.
The carnival stage is also a trip. There are so many little things in the stage that make the game amazing. I won't go into further details, though, so as not to spoil anything else.
The melee weapons are great, but very situational. Some people are still in the "new car smell" phase and can be seen running around wide open areas getting beat on while they try to smack a zombie with a crowbar or baseball bat. Melee weapons work much better in smaller, tighter areas. They also do a lot of damage to special infected, but I encourage all to NOT melee a spitter to death. They are a new special infected that spit a noxious acid at your group that bubbles on the ground for a few seconds. They also leave a mess of this stuff after death. I prefer double pistols over a melee weapon, and the new magnum (8 rounds, can't be dual wielded) is definitely the best secondary weapon choice. Ok, second best, but blowing up zombie heads with a pistol is great. The chainsaw wins the "best secondary weapon" prize, because it is a BEAST! It has a very limited gas supply that can't be refilled, but the weapon itself will annihilate everything in sight. I had a hunter leap at me while I had the chainsaw out, and I hit the attack button a split second before the hunter would have pounced on me. I killed that bastard without taking any damage! It was sick. Melee weapons & pistols are often found lying around places, but the chainsaw doesn't show up often. Grab it before anyone else in the group can, IMO!
L4D is one of my favorite FPS games. I could play it over & over again. I thought it was perfect, but now L4D2 makes me realize how much better the game can be. I haven't even had a chance to try the other modes yet--versus, survival, scavenge, and realism. If you love living out zombie apocalypse scenarios you will love this franchise. If you want the latest & greatest way to do it, buy L4D2. You won't be disappointed.
Now if only I could buy some free time so I could play this damn game more often I'd be set!