For me, the QuadraJet's were great carbs back in the day. When they work, they work great. When you step on the gas, and it's like flushing a toilet, throw your Quadratoilet away.
As for what to replace it with, there are a lot of options out there. Holley's are awesome, if you know what you are doing. Edelbrock's are a lot easier to set up, and the price is similar to a holley. You can run an adapter on your intake manifold, but if you look on Ebay, you can find a used Edelbrock (or Holley) manifold for about 2/3rds the price of new ones. Look for rebuilt carbs on Ebay too. If you don't dare swap the manifold on your own, (probably because of the distributor) it would be cheap to do at a local garage.