when you say the zeiss is the sharpest wide open do you mean zeiss macro f2 at f2-vs- the L's at f1.2? This reminds me of what Roger at "lensrentals" found during his big 50mm roundup. If you don't care to find that info and read it, i'll give you the short answer. The Zeiss(s) have nothing on the L or the 1.4 or 1.8 for that matter. In fact the Zeiss 1.4 is probably the worst performer i can think of off the top of my head in regards to the commonly tested lens areas. but you don't have to believe me, I've seen it perform poorly at maybe 4-5 of the top lens reviewing sites. search it.
But if you just want a solidly built MF 50mm lens that you can take pics with, at any price, that's certainly the Zeiss. If you get one that is calibrated properly, unlike the 21mm Brian from "thedigitalpicture" had. I know it's hard to believe, but for that much money, and with no AF complications to deal with, and all those "papers" with people signing off on them, they still get stuff wrong.
Oh, and the Zeiss 85mm is also a poor performer in the traditional areas of performance. Easily bettered by the canon 85mm 1.8 and sigma, but it's all metal, and you have to MF, so that's got to be worth something?!