MOO3 is both good and bad. It depends on your expectations.
It is NOT!!!! MOO2 with more features.
It does two things; first it makes things vastly more complex...
... and then makes most of the processes visible, modifiable, but automated, ending up near MOO2 in complexity but with much, much more depth if you want to dig in. That does make it a lot harder to do things though, leading to a steeper learning curve than really necessary.
It's a good game, but it is very different from MOO2, which is probably why it got some of the low scores.. that and being awfullly clunky.
Now it's a long time since I played it, but a sort of conclusion is, if you like it despite being different from MOO2 you're in for a grand old time. If not... it will end up a dust collector on a shelf.