Both the DT880 and DT990 are outstanding "bangs for the buck" in their "Pro" variants. The DT880 Pro can be had for slightly more than $200 while the DT990 Pro can be had for around $175. At those prices they are two of the best buys in headphones.
DT880 = Semi-open and more neutral
DT990 = Fully open with more bass and treble
I havent lisented to DT880, only DT990 and DT770, ended up buying DT990 because of its oppennes and all around better reviews I read at the time. Using a simple Fiio dac/amp which reduces the treble a little I really enjoy the this headphone. It really is a good bang for the buck at that price point.
I should also add that its bass slam is very nice and rivals XB500, and over all in cotrast to XB500 as a basshead's headphone I think its bass is more controlled and detailed without ever leaping to mids and bloating the sound.