Definitely a heavy gun. Long barrel is sexy with a bump up in fps, but is bulkier and heavier. Accuracy wise... well, with the nice increase in fps, you can use heavier BB's which is better for accuracy and consistency whilst maintaining similar range when compared to the shorter barrel with lighter BBs.
It's a trade off. Shorter barrel is a bit lighter and more maneuverable. It's amazing what a few inches off the length can do for you.
I stayed with the long barrel. If I wanted light and maneuverable, I'd use my MP9.