Picked up thousands of the bullets for cheap when they were being dumped. At full NATO pressure accuracy is OK. Drop it 100 FPS, and it tightens up and groups halved to pretty great accuracy.
I personally consider MK18 Mod1 the best general purpose bullet you can get. As to terminal, in theory the front core is "sintered" and designed to basically explode like a varmint round, while the back is harder and designed to penetrate. Giving you best of both worlds, and being "barrier blind" while also effective on soft targets. I would think it's terminal performance beats M855A1. It's accurate, if you are a reloader and it doesn't do weird things that require new mags.
As Molon says, it will over penetrate - so if your setting is one where that is a concern - there you go. If you're in the woods looking to night hunt Coyote's and Hogs out of the same magazine, there you go.