Mike, FWIW . . . there's an old saying among boatbuilders {& other woodworkers??}- ". . . you CAN'T have too many clamps !!
With clamps like these {and the wood-jawed clamps as well} it's a case of 'Form follows Function'. In cases like this it's a good bet that many of the clamps you see at supply outlets as well as the 'Harbor Freight' types, are made in the SAME factory in China.
Almost every time I see them on sale, I get a half-dozen or so {more in the
12" sizes for me, but I have them up to 50"}.All I can say is, if they are of a size you generally use and the price is GOOD - - BUY more than you *think* you'll use.
Regards & Good Luck, Ron Magen Backyard Boatshop