Here is a video of Silenced Marchall and how fun this weapon can be. I find it quite balanced unlike the Jackal single shot which is very overpowered and hopefully will be patched.
The suite modules i am using is nano recharge, stealth enhance and mobility enhance.
Tip for silenced marchall is always try and get close to an enemy, try and single them out, or out flank them, because of the slow rate of fire which makes fighting multiple enemies fairly complicated. Power jumping and using your suit to your advantage is crucial with this weapon as you do not want to miss a single shot.
Enjoy some insta action
http://www.youtube.com/watch?v=duEvsHEqnYs&feature=channel_video_title
... sorry for the poor quality of the pcture i get 25 fps average with frapps on, so the slowmotion didnt come out that well and the resolution had to be halved .