Clif Shot Bloks used to come in a square package. Open and with sweaty hands instant sticky mess. Now they are packaged in cello tube, squeeze one out a time. The Bloks also don't seem to be as greasy on the surface when damp.
3 flavors have caffeine: Cola, Black Cherry, and Orange. 1 flavor has extra sodium: Margerita. I prefer the Black Cherry.
I find Bloks easier to handle than gels for shorter runs. You can dose them as you go with no sticky package left to stuff in a pocket.