I have the sandman S for my 17s with stock barrel. The weight is definitely noticeable, but not too bad really. I run mine as a battle rifle with a TA11 ACOG and want to keep it light and short, without sacrificing ballistics. It suppresses pretty well. Too bitey for me without ear pro. With ear plugs it was very comfortable. I have bad hearing anyways, not looking to make it any worse. Offhand follow up shots are a breeze. It feels a tad overgassed with the stock jet. After speaking to Rod at Dead Air about the K on the 17s with 16" barrel, I ordered one. Should have it in 2 months. He told me they all liked the K can with the 16" barrel. My aim is to take the concussion out, cut noise down some, and make follow up shots quicker without having the OAL too long for my liking.
If I were running my 17s in a DM role and shoot from a bipod more, Id leave the sandman S on there. From my research, I would stay away from higher blowback cans on the Scar 17. The Sandmans seem like a good match for it. Love the Sandman line and all my dead air cans!