No matter which kind of base you use, the 2 you mention
cubes and the boxed liquids (not concentrated)
or casey's mentioned concentrated paste
my favourites are concentrated liquids
and there are also powders available
It all depends on how much you measure out. Yes, a lot of people choose by the various tastes. I've never sat down and tasted all different types. Although I've often had them just as a hot drink in a mug.
boxed liquids are wonderful and very convenient, open and pour. But they take up a lot of shelf space and unless you can find them on a super, super special - to my way of thinking they are comparatively expensive. I've never broken it down but a buck or two for one serving and approx 15 servings from 6 or 8 bucks.
Pastes and powders take time to dissolve.
I find cubes actually dissolve fairly quickly. Small pkgs, don't take up a lot of space - LOL but can get lost in the pantry!
Concentrated liquids take up the equal space of the pastes and powders. They are my preference as I find they dissolve so much faster ergo much faster to incorporate.
JMHO