Pros: Phenomenal SQ, like no other headphones I have heard
Cons: For me personally, a bit heavy and uncomfortable in long listening sessions
I had the pleasure of living in Toronto for 4 years and bought these at the excellent Bay Bloor Radio. BBR have a wall of headphones all fed by the same source, so I spent a few happy hours there on a quiet Monday night armed with a few favourite CDs.
I listened to AGK701s, a variety of Senns and all the Grados head to head. For me, the 325is (the Gold edition) were the best of the bunch, even versus the reference series models.
18 months and plenty of listening later (Arcam CD73T via a Little Dot mkIII) these still give me tons of listening pleasure. Some users report quality issues but I handle mine carefully, keep them on a stand etc and haven't had any issues.
I also read - before hearing them for myself - a lot about "unberarable" highs, but I don't find this at all - just a real warmth, immediacy and excitement in the sound.
After these, switching to other 'phones makes me feel like a layer has been placed between me and the music.
Haven't heard the "s" improved version yet but looking forward to an audition...