OK, here is the info on the Hoist quik-change dumbbells:
I played around with the 45lb set, but the 75lb set is the same except for the thickness of the weight plates. The weight plates are 5"x5" (just like the Probell 18) and have small grooves to make them fit together well so they do not rattle around or rub each other as you move with them. The dumbbell handle is just a threaded hollow tube with a thin plate to stack the weight plates against. The ends are big screws that screw into the handle as needed to tighten the weights against the plate barrier. I had to turn the end 3 wrist twists (NOT 3 full turns of the screw end) before I could take a weight plate out.
What I liked:
Because the ends screw all the way into the handle base when you have a light weight (only 1 or 2 weight plates), the dumbbell is only as long as a standard hex dumbbell of comparable weight. This is different than the Probell dumbbells which are 12 inches long no matter how many of the 5 available weight plates are on it. Foot-long 5 pound dumbbells just seem big and clumsy to me, but I am going to do some standard movements with a couple of rulers in my hands tonight to see if that would really bother me or if it just looks funny because I am not used to it. (Yes, I know I am a dork.)
The price is very reasonable for the amazing versatility in the compact size of the whole system. I located the dealers in my area using
http://www.hoistfitness.com/Hoisttest/html/dealer_locator.html and called around for prices. Some will sell you only the weights ($129) or the weights and stand together ($229-339).
What I didn't like:
The lightest setting for the Hoist 45lb system is 7.5 lbs. However, this can be looked upon as a good thing if you buy cheap 5lb dumbbells because then you can quickly change to your lightest weight without having to adjust your heavy one.
Even though it is pretty easy to adjust the weights, you have to adjust both ends of each dumbbell. I estimated each adjustment takes about 4-5 seconds so that is near 20 seconds to switch weights. Of course, here is where the Probells win--you just set the dumbbells down and turn a dial and pick them back up.
I hope this information is useful. Please feel free ask any other questions here or email me directly.
I am leaning toward getting a set of Hoist 45lb dumbbells for my DH and a Probell set for me. Of course, we will have to eat peanut butter sandwiches and beans for the next two months to afford it. Hey, a built-in diet plan too!!