DT770/80 - "fun" headphone, really good for positioning in gaming, nowhere close to a reference sound, emphasis on bass that is uncontrolled, flabby, a bit bloated and that which overpowers the mids and highs
CD3000 - huge soundstage, excellent for electronic music, classical, and opera, little bit light on the bass for my tastes, highs spectrum slightly overpowers the rest and can make your ears almost bleed on hot and/or poorly mixed recordings
HD650 - does almost everything right and everything wrong at the same time, dark veiled sound that takes the life and energy out of recordings, slow syrupy signature that isn't fast enough to make music sound accurate, sound excellent upon first impression and then get extremely boring quite quickly
PL750 - well balanced headphone that leans slightly towards the bass end of the spectrum, nice soundstage, downfall is the slightly recessed mids and metallic nature of its tonality, acoustic guitars and other instruments just don't sound accurate at all and the decay is lacking, fast and decently resolving, another very fun headphone that excels with electronic music but falls flat with pretty much any other genre due to its inaccuracies
Edition 9 - improves upon the PL750 in every category, unfortunately it still can't shake the trademark Ultrasone metallic tonality but it is noticeably better, acoustic instruments still just don't sound spot on to me, excels with electronic music due to its excellent soundstage and amazing bass quantity and quality, clearly on an entirely different tier in terms of resolving properties compared to the PL750, if you like/love the Ultrasone sound this is the headphone for you
RS-1 - amazingly fun and colored headphone that adds emotion and life to the music, very resolving, wonderful midrange and overall sound spectrum, gets you involved in the music and toes tapping, weak in the soundstage department as it puts you on the stage with the musicians, beautiful for both male and female voices, typical awesome Grado tonality, downside is that it seems to have this signature that it applies to all recordings...but it's a good one
PS-1 - has a cleaner more sterile amazingly liquid midrange(one of the best I've ever heard) that removes a bit of the coloration the RS-1 applies(in a very good way), incredible decay, has a clear improvement in refinement over the RS-1 to the point where every recording doesn't have that signature applied to it, bass quality and quantity that amazes on every listen but can be overpowering with the flat pads, bowls only use with these is my personal recommendation, downside is weight which can be offset by affixing a Beyerdynamic leather wrap to the Grado headband(I now do this with all Grado models), I have currently never heard another headphone that produces a live recording so accurately, listening to my library of FLAC Radiohead concerts brings tears to my eyes, makes you lean back close your eyes and take the music in
GS1000 - don't understand all the mixed reactions on this one, clearly has the Grado sound signature in the mids but adds depth and soundstage to the recording which steers it away from the expected Grado intimacy, highs region can be a bit hot on poor recordings and if used in the wrong setup, bass is excellent but can also be overblown if not controlled, very light on the head and an amazing bargain IMO at the $600-700 range they sell for used now
HP-1000 - flat but amazing sound spectrum that presents exactly what is in the recording, awesome Grado midrange and the most accurate tight extended bass I have heard out of a headphone, one of those headphones that requires you to listen to it for awhile before it truly wows you(and it most definitely will), not at all one that will impress in meet conditions, out of the head soundstage that will downright scare you at times, wider in soundstage axis than front to back, Herbie Hancock "Headhunters" is a treat through these, bought these before the PS-1, sold them when I got the PS-1, sold the PS-1 and came back to them in the end, the accuracy kept calling me back, I'll never be without a pair
ATH-L3000 - take everything I said about the PS-1 and throw in an improved soundstage, lacks in that it is not quite as airy as the PS-1 due to the closed back, which to me is why the PS-1 sound slightly more real with live recorded music, but it gains from that a slightly tighter bass that seems to extend a bit deeper, very balanced sound with positioning and imaging that are jaw dropping and amaze on every listen, just slightly dark in nature but benefit wonderfully from a slight bump in the highs region on an eq, ooze build quality all day long