Marcy - adjustable dumbells - anyone used them?

Lanfear

Hi, I am thinking about buying some adjustable dumbells. Unfortunately my budget won't stretch to the Bowflex Seletech ones, but I found these and wondered if anyone had used them / heard anything about them? Ta.

http://www.amazon.co.uk/Marcy-25lb-Adjustable-Transformer-Dumbells/dp/B001LELEUO/ref=cm_cr_pr_sims_t

This would be for use with the ChaLean Extreme DVDs.