I have the Manfrotto 498RC2. I don't remember how much I paid, but they are around $100 right now. I have it on my lightweight CF tripod that I travel with. It will droop (sag) a fraction from where you lock it down, but really only notice it at close macro distances or at 300mm.
It is smooth to adjust and can change the amount of friction depending on the lens. I would prefer that it would lock down like my larger tripod/head, but I don't carry that one anywhere.
You might want to check if you would prefer to use the Arca-Swiss type quick release and not Manfrotto (of which I have three different sizes right now). There are some Sirui ball heads that are pretty nice in the $100-200 range that use the Arca-Swiss plates.