WOW! That is all that one must or can say about this extraordinary optic. Most people I think would use this for portrait work, but why stop there. The glass is so crisp that wedding photographers and sports photographers would be crazy not to spring for this glass. I use it mainly at such events.
Optical performance almost flawless; Fast; fast; fast (only one faster in the world - Canon's 1.2L; Weight - not too heavy and feels very solid; Size; Metal hood; not plastic; Confidence it offers the low light shooter; 77mm pro size filter thread (same as 17-55 and 70-200
Price is a bit high for a prime (only in the sense that the 17-55mm AF-S is the same price and offers more flexibility; Lens hood cannot be reversed (threaded) for shorter storage; Would be excellent with AF-S though focusing is not particularly slow on D2X