The Shure SRH750 are tame basshead cans. They are bassy if you compare them with say, an Audio-Technica M50. But they are pretty much entry level basshead cans as far as excitement goes. The HFI 580 and PRO700MK2 both punch harder than the Shure cans, have better mid-bass and sub-bass levels and are cleaner in its overall sound presentation. The SRH750DJ is in between the Ultrasone and AT cans as far as tonality goes - the PRO700MK2 is dark, and the HFI 580 is the brightest of the lot.
Still, all 3 cans fare well with amping, and the Shures do sound a lot better with a bass boost amp, or with a good DAP EQ (like on the Cowon players).
If you're deciding between the 3, just get the HFI 580 or PRO700MK2. They won't disappoint; the Shure might.