I know these aren't really comperable planes, but I after getting my tailwheel endorsement last Spring in a Cub, I finally had the chance at a Citabria last weekend.
They both fly nice and light and are very balanced. When in the Citabria I missed being able to fly with the door open.
Now for the real differences. Taxiing in the Citabria was much less responsive than in the cub. I never really touched the brakes in the cub as the tailwheel was quite effective, but I had to use differential braking in the Citabria to get it to turn at all. The benefit of the Citabria was sitting in the front seat and actually being able to see what was in front of me without having to do S-turns!
Takeoff in the Citabria was much less exciting than the Cub (a good thing). Whereas the Cub rudder is extremely sensitive and easy to overcontrol for a newbie tailwheel pilot, the Citabria rudder was less responsive. The Citabria also seemed less willing to dart to the side if not perfectly aligned with the runway. The cub wheels on pavement seemed to have a lot more grip and any angle off center had much more effect.
We did a three point and a wheel landing. The three point was made easy by the fact that you can see the runway in front of you which helps give perspective for proper attitude. On my first shot I had the tailwheel touch slightly just before the mains got down. After touchdown, the Citabria seemed to keep rolling for a while and needed brakes to slow her down before the intersecting runway. I never had to use the brakes in the Cub after landing to get her slowed. There was probably a good 10mph difference in touchdown speed, and I wonder if that was the factor. It was a tad weird using brakes after touchdown, as that was discouraged in the cub. This was all done on the verge of being sick as it was after my first aerobatic lesson!
For a slow summer flight, I would pick the Cub hands down. Nothing like flying with the door open seeing everything below, with nothing more than a stick, rudder, and throttle to worry about. I would consider a Citabria for my first plane as it can actually cruise with the bigger engine and the ground manners are a bit more benign.