hmm i was just about to order the rhinox diffuser but saw this one too.
what's your co2 setup? is it a fixed output or adjustable? what's the outward pressure you have it at?
Granted, nothing is really wrong with Rhinox. It just depends on the style of diffuser you prefer.
As far as the comment about "cheap" ceramic discs go, I've had more and finer bubbles come from cheap eBay diffusers (the up-aqua ones) than I've had come from a brand new $140 ADA Pollen Glass Mini. I think each ceramic disc is a bit of a hit and miss situation, but that's just my personal opinion.