I received X-treme FX this week. I'm happy with the quality of the sound. There is a list of all the sounds on the site. If you like or dislike the list, theres not much more to know. My personal opinion is that it is overpriced by about a hundred bucks. I picked this up because it rounds out my library. Overall .... I'd still do it again.
There is a plethora of short punchy sounds that will go well in a drum mix. Like the door sounds, explosions, metal on metal, ... They seem ripe for some kickass drums.
I'd rate the atmospheres as a B- ..... Some good ones, but a little shy in this department.
Lets just say half of it is good and half of it is crap.
It's something you buy when you have everything else covered.