I own both and use them quite a bit, primarily indoors and when I want a light weight or less conspicuous lens. As others have pointed out, the 85mm 1.8 is a better lens. Sharper optically with faster AF, a terrific lens for the price. But, 50mm and 85mm are different beasts and serve different purposes.
I feel the 50mm 1.4 is the best price/quality combination 50 available with AF. Hopefully, Canon enhances their 50mm prime lineup this year with a new IS lens that is of similar quality as the other IS primes introduced in 2012 (24mm, 28mm and 35mm).