I bought a couple Besseys and one Wilton clamp before I discovered Strong Hand - now I'm up to 12 each of the 8" and 12" 1200 lb. 4n1's - I've done a couple projects where I needed a couple more, that's about the ONLY time I reach for the "name" brands.
I was an Enco customer before MSC "absorbed" it, still get Enco's lower prices (sorta) so the $50 clamps come to me (free shipping) for $20-25 each. Still adds up, but slower
The often heard comment about "can't have too many clamps" is even MORE true if you work ALONE like I do - those 4n1 clamps come with a "step over" adapter, pipe adapter (like their magnets Ryan mentioned, but without magnets

) - they also REVERSE to become a spreader. VERY versatile.
Oh, and no I'm NOT a salesman, just a "happy clamper"

... Steve
A few examples of "happy clamping" - outer half of my container roof is in 3 identical modules - bolted together while hanging from the inner half of the roof, then swung up as one unit. All 3 modules done on jack stands on gravel, all dimensions and planes accurate to less than 1/16", most less than 1/32".
Helped to have a few "shims" and a Wixey digital angle cube, but all were pre-drilled and bolted up almost like I knew what I wuz doin'
