The SAW's actually decent at mid-long if you burst fire it. Nowhere near as powerful as the precision weapons, but it will still beat an AR/Suppressor any day of the weak.
Thing is, the SAW is a power weapon, so the only way these two can compete is if we are going off of preferences alone.
Personally, if there is a SAW to my left, a Suppressor to my right, and I am completely out of ammo I'm going with the SAW.