I think the current ongoing is better than Kingdom of Monsters, but not by much. It starts off decent enough in the first few issues but the overall story (group of kaiju bounty hunters neutralize several Earth monsters, who are then trapped on Monster Island, just before an invasion of space monsters befalls the planet and we need the Earth monsters to defend us) is way too thinly stretched across 11 issues and counting. There is so much filler and action movie cliches it's ridiculous. While #10 and #11 have really delivered the goods in terms of a climactic third act, they should have happened months ago. The whole series could have been condensed down to five, six, maybe seven issues at the most, but they decided to make this one very basic story last for an entire year.
It's still better than Kingdom of Monsters, though, which was a sloppy mishmash of unfocused writing, bad art, unsubtle political commentary, and even more go-nowhere plotting.
Just pick up the trade paperbacks of The Half-Century War, Gangsters and Goliaths, and Legends. Those are the gems of IDW's run. The former two are succinct, well-written stories that are perfectly paced across five issues each and the latter is a collection of five one-off stories. I'm really looking forward to Rulers of Earth.