Hi Daviiid~
In fact, I have some experiences with HD25, hfi 780(sorry not 580s, but I tested them several times), pro750 and pro900.
I returned hd-25s after I had used them for a week. The sound was great, well-balanced with "not great but good enough" sound-stage.
For sure, HD-25s are one of the best portable headphone. However, I wear glasses and usually use headphones for many hours, which means "strong clamp" of the HD25s was a big issue for me.
As for the Ultrasone family, I would say definitely pro900s is the best in all aspects except price
.
I should join the few people(Gwarmi mentioned) who are okay with pro 900s along with fiio e11 for a "portable use"
I have been with my pro900 for about 10 months. At first, overwhelming bass and sibilance of the pro 900s were something that I had to endure...(yes...it is expensive! lol)
However, after like 2 months( probably more than 400 hours of burn-in) they got much better: tightened bass and less sibilance( I am saying "less" since brightness(?) and analytical sound are the very signatures of the pro 900s.)
Actually,I did A/B tests between my Ultrasone pro 900 and other headphones like shure 940, beyer 880, 770pro, 770, and ultrasone edition 8, pro2900 and etc.
All I can is that the sibilance of the pro 900 isn't too bad. (I kind of like it!)
Plus, some "eq-ing" can help the problem of sibilance, and a proper desktop amp can bring the pro 900s to a different level.
(I know little about desktop amps. What I am saying here is that I can enjoy my pro 900s more with my desktop amp - not expensive one, probably few of you guys on head-fi heard about "Audiofeel ms15a", a Korean amp - ) )
Anyway, I think hfi 580, 780 and pro 750 are great headphones.
Between 580 and 780, as you may already know, 580 has more bass. For me, 780 sounds better since I really enjoyed the bass punch of hfi780 and its beautiful, yet sometimes aggressive high!.
In my opinion, you can't go wrong with the pro750. That's my personal suggestion for following reasons.
1. Simply, simply, the pro750 sounds better than hd-25, hdi580,780 (at least to my ears)
2. Comfort issue. They are more comfortable than others.
3. Not as picky as pro900 in terms of "amping" :
4. Price: cheaper than pro900, no need of an amp--> implied saving!!!
5. Listening to all genres?? Go for pro750, might be better than the pro900 for you.
Pro750 will be a significant upgrade from your current dre. studio.(no need to say, but any of the headphones mentioned in this thread will do it..)
That's one thing that I can guarantee 100%
(except comfortability. I do appreciate that of dre. studio.)
David
p.s. sorry for my English!
( I'm not a native English speaker and now about to sleep! <== critical)