For those trying out grados for the first time the Grado PS500e is easily their best IMO. It has all the details of the others or more but softens the 2k midrange spike and has a lesser more balanced treble. Makes for a relatively warmer Grado (still bright). Sadly I had to get two pairs to get one with good driver matching. Order from some somewhere you can return them...
I have owned/used the following grados and choose the PS500e.
PS1000e (scooped out mids, they call it soundstage, I call it messed up tonal balance)
PS500e (good, light/fast sounding and punchy like good monitors, a little bright still, I love the close vocals).
GH1 (a lot like the PS500e but more colored mids, you can hear the wood in the bass for better or worse)
GS2000e (uhm no, really bad, just no, ear tweeters, funky soundstage)
RS2e (brighter and less bass than the PS500e, small spike at 2k)
RS1e (I don’t really rember these...)
RS325(pretty bright, probably the brightest Grado I owned, ok other wise)
RS225e (light on bass, more open mids from the models down, a poor mans RS1/2)
RS80e (Best buy, most of the Grado sound for under $100)
RS60e (warmer of the grados. Tuned like the PS500e but less open and detailed acrossed the whole frequency range.