I've been using the SAM with Hardline and it's been a great asset. Even when I was completely terrible in all of my matches yesterday, I still averaged one or two spy plane kills a match. I think I'm going to go towards Ghost with a silencer though. I figure that staying off people's radar the majority of the time will help me get that extra kill towards a SAM that Hardline helps me with right now, so hopefully it will be a win-win.
Wait till you get Hardline pro. You can then reroll the Sam the same as a care package. An the reroll a better chance to get a higher killstreak. Confirmed by the games data files.
And speaking of the data files, all the info on the guns damage and recoil etc is now know, and it's really disappointing how similar they all are. Within each class fire rate, recoil and reload times vary very slightly. In some cases there are weapons that are simply mathematically better than others - for instance, the commando has a 25% shorter reload than the ak47, everything else is equal.
As far as actual bullet damage goes, all ARs are either 25-35 or 30-40. Which outside of a practically negligible midrange difference, and an extra shot required at distance in hardcore, the damages are identical - 4 shots at distance, 3 close up. MW2's weaker ARs were 30-20, which translated to 4-5 shots without stopping power.
Same basically goes for the other classes, all the damages are nearly identical. I guess it's easier to balance everything by basically making everything the damn same.