I have all 3. Don't use the 50/1.8 since getting the 1.4. The 85 is by far my favorite but it's usually too long indoors (on a 30D). I keep trying to arrange situations where I can use the 85 on my kids...but the 50/1.4 is pretty nice too and gets the most use.
I've owned all 3... sold the 85/1.8... don't like the bokeh... am selling the 50/1.4 and keeping the 50/1.8... I hate the bokeh the least from that little lens. They are all sharp.
i've had all three. 2 copies of the 85 (both were great), one 50/1.4 (sorely disappointed), and still loving the 1.8mkII.
I really think that the 28/1.8 should be up on this list as well, as it just never ceases to amaze me. Great lens- tiny, light, fast focus, and good optics (for the price). The 35/2 is always raved about as well- but i have no experience w/ it.
Have owned all 3. The 85 is very sharp wide open, better than the others. Bokeh is OK in my opinion but watch the purple fringing, you can see on the edge of the white helmet. Both are wide open, 2nd is 100% crop:
50 1.4 was not as sharp wide open. I kept the 50 1.8 because the price is right for how little I use this focal length, a true best value lens. Just don't drop it.
I have all three too, used them since my film camera days.
However I didn't use the 50 f1/8mkII much now, because a long time back I brought the lens and my film SLR to Whitesand, and the 50 f1.8mkII liked the dessert too much (it collected a lot of sand inside) The 50 f1.4 is much better in this regard.
the 85 f1.8 bokeh is really great. I mainly use it for portrait and the result is very good most of the time. I actually prefer the 85 f1.8 for portrait than my 28-70 f2.8L...
I bought 50/1.8 MkII first, then upgraded to 50/1.4, never looked back. Excellent lens, much better than any L-zoom at any comparable F-stops. I bought and sold 85/1.8 couple of times, tried to like it, but clearly 100mm f/2 suits my needs better. IQ wise they are practically identical, so if 85mm is the focal length you use - go for it.
I'm looking at getting the 30mm sigma 1.4, its only for crop bodies but has great performance at a great price. Seen some comparisons which have it trump the 50 f/1.4 in numerous ways (sharpness, contrast, etc).
I have the 85/1.8 and have had the 50/1.8. The 50/1.8 I had needed to be stopped down to f/2.5 to be sharp, which was only a minor improvement over my f/2.8 zoom. The focus was slow and poor, but for $75 it's still pretty good. The 85 is far superior in AF speed and accuracy, and you really can use it at f/1.8 - i.e. it is very sharp. I have never owned the 50/1.4, but I definitely do like the images produced from it. I would probably rank them in the same order as your list for great image quality. The 85 may not be as versatile on a crop camera but, for performances or portrait photography it is excellent.
I have the 50/1.4 and the 28/1.8 (which I also think should be added to the list as suggested by "ISO1600"). I use them all the time even though I also have the 17-40/4. Each has their own strengths and weaknesses, but I really like the sharp, light handling of the two primes - not to mention a noticeably brighter VF in lower light.
... and I think that particularly the 28/1.8 is an underrated lens - it will always have a home in my camera bag!
So far, I have no experience with the 50/1.8 (either of them) or the 85.
I have the 50 1.8 and the 85 is on its way as well; I have also been thinking about the other primes. Mainly because with my first few ultra-sharp shots from the 50 at such a great price point, I quickly got addicted.
