Pros:

Disgusting ball of meat
Totally badass
Like a mutant head crab

Cons:

Harder to see, sort of

Conclusion:

There's no reason not to use this. This is miles cooler than the default Jockey and is easily the best Jockey skin on this site. 

Pros:

Ambitious
Looks just like the screenshots
Pretty big and bad ass

Cons:

Doesn't fit the L4D2 theme
Sticks out from the other Infected

Conclusion:

It's big, it's badass, and it's apparently from some game I haven't played. I can't give it shit for not keeping with the theme of the other infected, so I guess I'll just have to give it a good rating. 

It's pretty nice. Give it a download.

Pros:

Distinctive look
Makes it easier to see bile

Cons:

Absolutely nothing

Conclusion:

It changes just enough. It's not an ambitious mod, but it does exactly what it says on the tin, and that's fantastic. 

Pros:

Good texturing
Cool idea

Cons:

Doesn't fit with the rest of the SI

Conclusion:

I really wanted to like it, but had a really hard time. It's really cool, really monstrous, and really nasty. It doesn't fit the theme of the other Infected well enough, though, and that makes it a lot less fun to use in-game.

It's awesome if "continuity" doesn't bother you, cause it looks terrifying in game.