I have the HCD 28mm, HC 50 II and 120 Macro (the Mark 1 original version)
First, the older 120 Macro is very good, pin sharp. Might save a few pennies if you buy one of those instead of the MkII version - doubles up as a fine portrait lens.
HC50II is probably the sharpest of my lenses, and a great upgrade to the original design, which was a bit soft.
Everyone says how good the zoom is but it is big and heavy.
As I have just three lenses, I lug them all around if I am out and about.