rdenney wrote:
You may find the 50/1.4 to be bitter-sweet, too. If you think it's hard to focus reliably at f/2.8, then f/1.4 is going to present even greater challenge. But at least the autofocus will be faster and more accurate at the wider aperture.
Rick "who experimented with the lens in deep dusk and really depended on the autofocus" Denney
Thanks Rick.
I had the 135 f2.0L for a while and did find that difficult to focus - Not expecting the 50 f1.4 to be as difficult. Mainly, it was a matter of being less cavaleer about shooting - I actually had to take care and be deliberate. I think the enforcment of being more deliberate on each shot is a positive exercise.
Haven't found my 50 f1.8 troublesome unless the lense actually misses it's mark (on a stationary subject usually) - not too common but often enough to cause frustration. Ergo; this upgrade.
ed2day wrote:
If you can afford to keep the 50 1.8 and buy the 85 1.8 it would be a no-brainer for me. As was stated previously.
Thanks. The 50's in the mail already. However; as stated above, I'm opting for the better 50 to decrease my equipment failure excuses. The 85 f1.8 has been on my wish list for a while, and considering it's low price, will probably be in my bag within the year. Next round.
Like a party that's best to leave while it's fun, or an audience that's best left wanting, I'll leave this purchase on the wish list for now. 
I occassionally take product shots (window coverings), so a 50 suits that a little better. The Tamron Zoom has filled that need well up to now, but a nice wide lense may have to be next.
rklepper wrote:
Yes, you cannot go wrong with the 85. I am really at this point using my primes more than my zoom (only have 1 left now)
I'm sure your work is better off for it. I most often am chasing kids around the park so a good zoom + 1 prime suits me. Having options for those lone afternoons when "daddy's off taking pictures" will be the next pursuit. For that; I see mostly primes as a worthy goal.