I checked the numbers at wiki. Better than sniper rifle, worse than Gobi it seems.
Not true if you have WMX installed but from a console user's point of view, I guess you're right.
Umm Christines has about 14 more DAM so youre wrong...
Check the critical damage.
Time for some math. We're going to assume that the Better Criticals perk has been selected.
Because the COS has a higher crit multiplier, it is more likely that it will inflict critical damage. It also has a higher base damage, so non-critical hits will do more damage and the damage will get more effect out of HP and JSP ammunition.
If we assume a 20% critical hit rate, the expected damage for the average Gobi shot is 96, compared with 108.5 from the COS. The Gobi does 13 points additional damage on every crit, but does 14 points fewer damage for every non-crit. The Gobi slightly narrows the expected damage gap as the players critical hit chances increase, but it is hardly significant. When HP or JSP bullets are used, the expected damage gap increases in favor of the COS.
Note that this does not factor in damage from sneak attack criticals, as either gun is going to do enough damage that whatever you shoot at will either be dead or close to it, especially if you hit it in the head.
Other factors:
The Gobi weights 1 pound less.
The Gobi has nearly twice the item HP, requiring fewer repairs.
The Gobi has one additional bullet per magazine, reducing the frequency of reloads.
The Gobi requires much less AP, generally allowing for one additional shot in VATS.
The COS is silenced, permitting easier concealed sniping.
In summary, both guns output similar levels of damage, but the COS tends to scale better.