These clamps might be considered the industry standard, so it's no surprise they are well made.  There are good clamps available with features these don't have, such as taller, broader bases or built in hanging hooks, but these do everything I ask of pipe clamps and the quality of the castings and machining is excellent.  When I bought them at about twelve dollars apiece the price was a couple of dollars or more less than any I could find for comparable clamps.