... there be no question , this type of all-in-one adjustable multi-weight dumbbell be extremely attractive in term of save you space and money versus buy several set of fixed-weight dumbbell , and save you the tedium and time of change plate on conventional dumbbell even if you use those tension spring-clip . however , do not expect perfection ... the inevitable downside be that the double-pin mechanism use to change the weight on these powerblock can itself be a little tricky at time . definitely not ideal if you be into high-intensity training -lrb- multiple set at different weight level without any rest period in between each set -rrb- . in fact I prefer the change mechanism on the Bowflex dumbbell though as the other reviewer have state , the Bowflex dumbbell be not only considerably more expensive but also have suspiciously flimsy design and build quality in comparison with these powerblock . so in a nutshell , if you have the space and money , I would still recommend spend the money and space to buy several set of hexagonal fixed dumbbell ... the speed and convenience be still far superior , especially for high-intensity workout . if you do not have the space and money to do that , and can not or do not want to go to a gym , then these powerblock be indeed the best available option I have ever come across . keep my finger cross that at some point in the future , technology will have evolve to create a truly quick and easy one-touch weight-adjusting mechanism !