free float tubes
free float tubes can give better accuracy per se..
but remember its also soo easy to think our 16" m4's are sniper rifles.
i see free floats as finishing touches of accuracy.
take a look at your trigger.. that crummie wolf you shoot. (hey its whats i shoot too

) improve your technique.
to be honest most modern day rifles are usually more accurate than the shooter is capable.
if you were leaning towards a midwest handguard.. i would def say save some money... get a non free float and put the money saved into a better trigger and good ammo if your looking for accuracy..
if u practice alot.. match trigger and barrel.. and u know there more accuracy left in your rifle.. i def so go free float.
my .02
edit... free floats obviously have their big advantages if you are going to be mounting optics on it... then its a no brainer to go free float.. but u showed a non railed one so i figure your not going that route