Today I put on some CST Big Boat tires to replace the Kenda K-Rads.
I ride mostly on pavement and the Kendal's are a total drag and really loud. The size difference isn't that significant but the street pattern and slightly narrowed profile makes it a total winner on the road. I went on a 3 mile gravel loop today as well and the difference is minimal.
I only think the Kendas are worth it if your trips are always on dirt or sand. Otherwise I'd say they are mostly for looks and to alert pedestrians of your approach from 20 yards away.
The acceleration is also faster. The CST's are noticeably lighter.
Front wheel.
Da rear.