Well, all the upsides have been stated for me, so here are my cons:
Shotguns ARE over=powered. KOG Elusive is correct. Being able to shoot someone once and kill them after they shoot you three times to the chest is not realistic. Thats Halo 3.
The inability to mute people while the game is loading. Its my own small pet peeve, but it blows when someone is being quiet, then the game starts loading up and they get really loud and obnoxious.
The music in online play. I have died so many times because of the music that starts blaring. I wear Turtle Beach headphones, and the music starts blaring and kills my eardrums. So someone runs up behind me and stabs me.
The accuracy and power of machine pistols. Haha, hey, I use them, because they put out alot of firepower and are highly accurate, even when akimbo-ed. Just add a silencer. Still overpowered.
oh, and I believe that the kill cam needs to be changed so you don't see every action of the shooter. Its too easy to then respawn and kill them. Change it in some way. And the last kill of the game should show the viewpoint of the bullet; in the way they show a throwing knife flying into the air or something.
Last, but most importantly.... MUCH MUCH more importantly: NEW AND MORE BALANCED MAPS
I'm sorry, but no matter what someone says, quarry is NOT a balanced map for SD. If it switched off on sides after every round maybe, but not three consecutive rounds of offence or of defense. Thats unfair for one team. The defense part of SD is so overpowering of the attacking team. There are few maps where defending is difficult (I'll give you Wastelands, that can be tricky) But beyond that, spawn tubing is a big problem. On almost every map, you will get spawned tubed. Says something about the design of the map. (or that too many people have too much time on their hands) .
Beyond that, I do really enjoy the game. I think its very cool being able to tweek your weapons just the way you want. It may sound like I'm ranting, but if I decided to say why I like this game, the post would be way too long!
happy slaughter~!