Shure SRH1540 --> Note, this is all from memory
Comfortable, Great built (surprisingly light and robust at the same time... weird lol). Excellent pads. The biggest "con" for me is that the bass was a bit too eager, overbearing and it intrudes on the mids. This actually makes them sound warmer and couple that with polite highs and well, it's enjoyable but you feel like you are missing something (especially when comparing against similar headphones). It feels like some "air" is missing and suddenly you just have a nice sound kind of veering into "meh" territory. I wrote on my initial review:
Separation and imaging was aces and the mids were good as well, just be aware of the above sound signature and you will enjoy them. I actually liked them. The main reason I got rid of them was leakage. Yeah, these leak sound and I'm not one to listen to extreme volumes but when someone on the next cubicle is singing along to the song you are listening... yeah, not good. Now, they don't leak Denon Dxxx/Fostex TH-xxx levels! But they do leak.
DT1770
Comfortable (but these weigh quite more! Or at least they feel heavier.), Built like a tank! Good option of velour or leather pads (I prefer the leather pads on this one). Now, bass on this one is ALSO elevated, but not as much as the 1540s as I remember. Mids are not as "smooth" as the Shure's (for some reason, Shure always excels on mids, at least to my ears.). Highs are definitely boosted. This provides that missing "air" the Shure's lack but also lacks that certain semi-artificial Beyer coloration. Do note, I like it.
This makes the headphones a bit more "exciting" and more "lively". Well recorded tracks sound excellent. Poorer ones sound extra crappy (I guess due to that "artificial" boosted highs nature -- 1540s fare a bit better due to the "muted" highs).
Separation/imaging is great as well, though I remember the Shure's being a bit more exact when listening to certain classical and salsa tracks. But the Beyer's are no slouch. If pushed a lot, these will leak a bit as well (especially with the velour pads for some reason) but not 1540s levels.
Overall, I personally like both.
If you want a more comfy ride, decent bassy sound, listen semi-loud and don't care about leakage, the Shure's are a very decent option.
If you want worker bee headphones (
), with a decent overall signature, solid construction, and don't want to look dorky (I hate Shure for always making their headphones extend outwardly... ugh! LOL), Beyer's are a good option as well.
Now, regarding $$$, if you can find the 1540s at $350 or less or the Beyers at $400 or so, those are a decent deals for them. Why would I not recommend them at their full price?! Just because it has become more difficult recommend anything at their full price... (this industry is just moving way too fast!!!) Do note that both come with: Case, extra earpads, 2 cables, etc. so, price might be justified when compared with cans such as Fostex TH-600 or X00, Oppo PM-3s, Audio Technicas and others priced similarly and not providing even a solid bag...
Anyway, those are my .02 cents.
Good luck.