i did a test on this recently and the silenced M4 was way more accurate then un silenced but un silenced is more dmg but not alot
really? do that test again a different way or something, because they are the same. silenced or unsilenced the m4 has a set of spray patterns (just like every gun in the game) so basically the accuracy is the same.
the damage is different however - headshot difference of 83 silenced and 91 unsilenced (give or take depending on the situation) and thus silenced can actually make you use another bullet for a kill if you hit the head and leg or something.
another difference is the sound/stealth factor, which is very situational on its own. keep in mind you are generally facing where the enemy is, they are doing the same...so even tho they cannot see your muzzle flash they don't need to because they are looking right at you.
if you are behind them and shooting nobody will show up on radar, silenced or unsilenced (little myth here) and either silenced or unsilenced they will know where you're shooting from because of the red damage indicators.
i basically find silenced near pointless and rare where its actually helpful (shotting through smoke/bushes). i prefer the damage of unsilenced.
however there is a right answer to this question, and it is:
whatever your mind plays better at. yes the mind plays tricks on us, like making us think silenced is more accurate so you are better at using the gun when silenced etc. so whatever your mind decided, play to that decision.
edit: i found this kool link that could help yas
spray patterns