Ok. Haven't listened to these drivers for awhile. I just finished the Amboyna based set this evening and had just recently finished an HF-2 set and sent them out yesterday.
The biggest difference I can tell you is a more engaging sound with the Magnums. I don't have golden ears and have never professed to, but I can tell you that the Magnums pull me into the music, enveloping you with sound, and while I still really like HF-2's, 325's, and certainly still love the RS-1's, the Magnums have the dynamics that are really engaging. To each his/her own and everyone has to decide for themselves. I'm just calling it like I hear it. Bare in mind, I'm only comparing the Magnums up to the HF-2's/RS-1's. Any further up the Grado chain I don't have experience with, except for a set of SR-200's with the Black Star Drivers that I've borrowed a couple times but that was early last year prior to my current setup.
The Magnums aren't going to be as accurate and can exhibit some pretty bloated bass action, but by golly, it just works for a $120 set of drivers. No sibilance. Toe tapping. Bass thumping. Good.
Magnums go well with some Black Keys.
Also, the advantage of the Magnums is they are easy to drive. Yes, Grado's are easy to drive, but they are thin in comparison. Magnums excel unamped and improve upon that with good amping.
I'm thinking peeps out there should try these out with the jumbo bagel pads again. I'm going to pick up another set to do some comparative listening when I get a chance.
And by the way...I have no affiliation with Rhydon over at Symphones Magnums. I can whole-heartedly still recommend 325's and above from the Grado line-up. But I'm just saying that you might want to look into the Magnums as well.
What I can say, is that Magnums probably aren't going to be that accurate for classical.