I have a M4, and have A/B'd its pres against several other pres, including the RNP (but not the Grace 101). The M4 is a decent board, the pres are certainly better than Mackies, but not quite as nice as the RNP, at least to my ears. One thing nice about the M4 is that you can line in outboard pres into the board channels and utilize all the other features of the M4, which are rather robust.