Believe it or not, the Hardballer shotguns are among the best cheap springers you can buy. I've got one and several other people here bought one for playing indoors at Xtreme Tactics during springer-only games.
They're by far the quickest springer to shoot; you can hold the trigger and keep pumping. The foreend is spring loaded so that you only need to pump it back, then the spring shoots it forward for you. It fires around 150 fps with a 0.20g and is pretty durable for a spring gun. Too bad about the transparent clear construction, but that's what Krylon Fusion is for.
While I was reffing a game at XT once, one side was getting schooled pretty badly. When this happens a team member will sometimes come in and play to even things out. Out comes Ding with his Hardballer and totally owns the other team who's all using AEGs or GBBs. Just goes to show that the cost of your equipment isn't a determining factor in how good you are.