The Rocky has been in several grinder comparisons, and has always lost against the Mini and the Innova/Lux style conical grinders. This is not surprising, since the testers were making 17 to 18 gram doubles, and the Rocky pretty well sucks at that dose, the worst of all grinders tested. The big news for Rocky owners is that it is an absolutely terrific low dose grinder, the best of the group tested so far. So if you own one, get yourself used to making 12 to 14 grams shots. For prospective buyers, it's harder to give advice. Most Silvia/Rocky buyers seem to be looking for Vivace like shots; and this setup isn't even going to get into the same zip code, never mind close. But the Italian sized doubles from this combo were, quite simply, great.
Source: home-barista.com