I agree with everything in this review. This game is very fun and can get you into some real nail-biting, hilarious moments. On the flip side, you could find out that your factions suck as a 'team' and usually whenever anyone plays zombies, they'll win most of the time (To which I have found either banning them or making them unable to be selected by anything but 'random chance' helps). Still it's a very nice competitive game that will keep you and your friends amused for a good deal.
I also agree with the part about the expansions, a LOT of folks seems to dislike the Cthulhu expansion, while everyone who loves this game owns the awesome level 9000 expansion. I bought the Sci-fi one and tbh, yeah take it or leave it really, if you are looking to expand your collection, get it, otherwise awesome 9000 and the base are basically the only things you need.
On a side not, I love how the fact that the base set's box allows you to store up to two expansions in it, very smart and very handy.