Living in Belize, sit-on-tops are pretty much all you see. And they work great down here where the water is warm -- sit inside get awfully hot in full sun and warm water. That said, when we lived in NC we had touring kayaks, and they were great for flat-water creeks and rivers, especially on cooler days. On hot days they were a bit much, but they do keep at least most of your legs from getting sunburned! Sit-inside are generally longer, skinnier, and faster, and have more space for gear compartments, if that is important to you.