Just got the 24/40 Bessey set that I ordered from Amazon last week ($100 delivered). All I can say is now I know why woodworkers like these so much. These are my first Bessey's - for the last 15+ years or so I have used pipe clamps.
First, I was impressed with the weight of the clamps - I never expected this - really well machined, silky mechanism & heavy duty.
Second, the operation is so simple, that I can't see how it would bind (unless you got glue on it or something). My pipe clamps seem to bind at the worst times during a glue-up. Now I know why Norm uses them.
Third, they have a nice deep throat (good movie title ;->). The pony pipe fixtures I use(d) have a too small throat for many situations.
Fourth, the Bessey block set that came with the clamps will make panel/door assemblies a lot easier & effecient.
Lastly, the price of these clamps ($25 each at this price) is not a whole lot more than buying the pipe fixture & black pipe.
If you have never tried a Bessey, you might want to give them a try. Amazon's current price of $140 is not bad if you use a $25 coupon, but if you check often, and see them drop to $125, you might want to grab one (and forget about Rockler).
From now on, my pipes will be back-up to the Bessey collection which I have only just started.
(I guess this is sort of a mini gloat).
Lou