This is a tuff one, "Drop" is keyword rich, OfDrop is a bit complicated IMO, are people going to see "of" as the actual word, or will they see "of" as a companies abbreviation, "DropOf" is the better of the two IMO, but i do see some possible development potential with this name.
A valuation price is tuff on this one as well, My thoughts are anywhere from $15 to $150 and a bunch in between IMO