I like it a lot. I ran it on a previous AK and it held up well on that one too. It mounts using the same 2 screws that you would use on a standard AK stock. The screws backed out after the first range trip, so I put some blue loctite on the screws and haven't had a problem since. I'm not familiar with the siaga 12's, but if their stocks mount up the same way, you should be good to go.
Where did you order it from? It looks killer.