These are by far the shotguns I use frequently in the game. Although one thing we need to note is that they cost gold. For me this means getting the free gold from Gun Bros 1 and downloading tap joy games.
Both are good and have their advanages. If using the Wonder Twins, you are sure to kill zombies instantly at close range. Even the fireman zombie gets obliterated with 1-2 shots. The disadvantage here is the slow rate of fire. This weapon is also not good when you are swamped by zombies in all directions. You need to frequently dodge a lot while you reload the weapon.
Overall, the Street sweeper auto shotgun is the best mission weapon. The 14 shots it has is enough to clear the way for you. It also has a high rate of fire. It reminds me of the slamfire of a Nerf N-Strike Alpha Trooper. The only disadvantage you have for this weapon is the range.
Personally, I have always use either one of these weapons but I really need to finish a stage with no fuss/problems then I will stick to the Street Sweeper.
Cheers. Comments welcome.
The Wolf Pack are my friends, like all others whom I have the pleasure to know. You have my respect because you deserve it - the same way I expect this respect from you as well.