for my personal experiences, i can only talk for the aluminum and titanium space case, mix n ball double screen, sharpstone, and a cheap, $15 no name aluminum i got at venice beach a wihle back. back when i didnt think much about grinders, i got the $15 no name. i didnt treat it that bad, or put big stems in it, but the teeth touched i think and after abut a week or so, a few of the teeth broke off. my next grinder was the sharpstone. worked great for a whlie, but after a couple weeks, i started getting fairly large metal shavings in the bud. this was copmletely unacceptable. it was then when i spent the money for the aluminum space case. ive never had a problem with that. time has passsed, and so have grinders, and the MNB has also proven to be very high quality, altho not my style. so with my experiences, space case is th eonly way to go for me. but in terms of quality, the MNB is right up there too. the sharpstone and other cheaper brands work great too, and they'll probably be sufficient for most. but with my experiences, these still tend to have more problems than a space case. so i still believe u get wat u pay for.