I have the AAC Orion can for my H&K Tactical. I know they don't make it anymore but I assume what I am saying applies to their newer models as well.
Pros - When "wet", the thing is weally weally quiet. I mean you could shoot the last wabbit in a string and the front ones won't know it
Excellent workmanship, fit and finish.
CONs - I didn't realize is WAS a "wet" can. It also works dry but the suppression is much less.
I guess if I was an "operator" instead of a gun nut that likes to shoot neat guns in the desert I would love it cause those guys probably don't shoot more than a magazine. If they do they are in a real firefight and MR MP5 is probably brought to bear anyway
But, as a dummy who likes blasting stuff for no apparent reason I find it annoying to fill it with grease. And I don't care for the added mess.
So I guess I am suggesting you first decide if you want a dry or wet can. If you want dry then look at the specs for suppression by the various cans in dry mode and pick that way.