Pros:

The 4th map
the 5th map
music queues

Cons:

A ballon at a ship port when there are high up buildings seems odd
movement on the ship is awkward
prison didn't feel like a prison

Conclusion:

Before I say anything else I will try to tell you how good the 4th map is .... I love that map so much I am worried I might get it pregnant.
The 5th level design is genius, the only things I could find wrong with it were a missing path bug (if you stand on the boxes on the pier tanks would target you but were unable to get up) and that it was a little odd that a ballon would get to a ship pier when there are high up buildings where he could dock.
The first 3 levels are good too but they simply were nothing special. You have alternate routes, a few panic events and a prison without cells. I have to stress this, they are not bad they simply are in the shadow of the 4th and 5th map.
My conclusion: Download it, if they had voice acting you would assume they came from Valve.

Pros:

Very professionally done
many different settings
big areas
chaining panic events
Actually fighting to the top of a building

Cons:

even though there are 4 maps it feels a bit short
no real finale

Conclusion:

If you liked 'No Mercy' download this map, especially the last part felt a lot like it's pinnacle, the hospital.
The transition to the sewers felt a bit odd, during the 2 bridges event a charger ran into the water and couldn't find it's way up, I ran against a window frame in the "car alarm bridge" part and a bot suddenly decided to jump off the building when the helicopter was about to land are a few errors which could get fixed otherwise though great map.
Definitely a map worth downloading for multi and single player alike.

Pros:

Nice story which goes through the whole campain even if it is a bit obvious
Map is done nicely, a lot of effort
Finale is entertaining

Cons:

Skybox again broken on Mac
Finale is too easy since you can go into on corner

Conclusion:

You need to add additional spawn points during the finale on the other side of the room
There is a minor bug with a chest in a small doorway which tanks have a hard time passing
but overall:

DOWNLOAD THIS MAP

Pros:

Deja vu pure - If you liked Half Half 2 download this map
Alternate routes
Handles well with bots

Cons:

Finale could use a bit of work

Conclusion:

If you like Half Life 2 play this map, nuff said.
Finale could use a bit of work, it's kinda hard to find where it is you are supposed to go from the "Lead Resistance members across the shooting range" part
Infected have a very long run to the arena and are too easily killed before they reach you
Tanks handle a bit wierd
and Survivor bots keep jumping on the fence which looks a bit odd.

Pros:

Nice atmosphere
One exiting moment after another

Cons:

If a spitter spawns during the speedboat event you will get killed.
Speedboat event could be longer
If you stand on the chimney during the finale tanks will despawn and special infected won't target you

Conclusion:

I don't know yet if broken skyboxes are due to the mac client or a fault of the map maker but it would be nice if that could get fixed.
The speedboat part is interesting but could be a bit longer than 100 yards and as shown in previous reviews special infected don't handle well in that area.
Some minor flaws but over all still worth downloading.