I just bought this after a recommendation from a friend of mine and I must say I am totally blown away by the sound of it. In addition to my hifi speakers down in the basement I have a pair of Cube speakers on my desk (yes, the ones that came with the Mac Cube in 2003(?)) and this makes them sound extremely wide, crisp and clear and they are now able to reproduce frequencies that I never would have thought possible given their size. I have tried Hear, Volume Logic and iWOW and had nothing but problems with them. Volume Logic doesn't work with iTunes 7 and 8, so I can't use it. Hear wasn't effective enough for my taste, introduced some strange volume changes and required too much messing around with the various parameters until it sounded about right (to my ears anyway). Same goes for iWOW which in addition to sounding crappy on my speakers occasionally comes up insisting on being a demo version (even though I have bought and paid good $$ for this copy!! WTF??). Also, if an app comes with too many settings it always feels to me like the developer is hiding the fact that he didn't find a good setting that works with all music behind a s##tload of parameters, and no matter how long I tweaked iWOW and Hear they never really sounded right. Not so with AstoundStereo. There's not much to tweak here, it simply works. I had occasional sound glitches (no kernel panics) after putting the machine to sleep (which is why I am giving it 4 out of 5 on stability) but IMO this is a minor issue since turning it off and back on always fixed the problem, and it affects my MacbookPro only anyway. All in all, this gets top marks from me. Maximum sound, minimum hassle - you can really feel the instruments playing all around you. And I like the fact that it has one big slider, too. True quality doesn't need 20 parameters - if this doesn't work for you you don't waste 2 months tweaking something that doesn't sound right to begin with. As far as I am concerned, this is awesome!!!