I am very happy with the RND R10 500 series rack. I particularly chose to buy this high quality rack (rather than a cheap one) because of the importance to me of ultra-low-noise signal paths. I have had no problems in that regard. It appears to be as compatible as it needs to be; I have used Millennia Media, Inward Connections, and AEA modules so far. The attachment nuts on the front have been designed to move a little, to suit modules with slightly inaccurately-drilled holes; to stop them rattling on unused slots, use little washers under the spare screws. The only disappointment is that it does not include some blanks to cover the unused slots.