Product review (5 stars): If that sounds like you, buy this
Three of the four wheels were loose and falling out on my Kenmore Elite (Whirlpool) dishwasher.  It was so frustrating, I had considered getting rid of the entire unit because the top rack would pop out of alignment constantly.

If that sounds like you, buy this.  It's what the design should've been in the first place.  Steel guides for the wheels, and a better adjustment mechanism.  Fixes the problem, and feels much more sturdy.  Go for it, you'll be glad you did.