Got all of them right at release. I didn't write reviews, though. If I ould have written them, All packs except aquatic and europe would be only positive. The aquatic pack is much better now and would now get a positive review, since they changed the deep dive requirement. For me, the animals basically weren't very useful before. Same goes for the Polar Bear, but we got other cool animals with the arctic pack.
The europe pack is a problem child for me. I love it for the damaged wall decals and for the high quality animals. Everything else is more for a city builder than it is for a zoo game and will always feel like an "excuse us, builders, that we sometimes focus on animals in a pack for a zoo game" DLC. There are even some props that make me irrational angry.

Like a problem child.
Unless something really bad happens, I'll continue to buy DLCs right away.