Having had the very good 'cheaper' cousin (85F1,8), I found that with my DRebel, I just wasn't using this focal length all that much. Once I switched to a 1D, 85mm suddenly seemed to work much better for me. I also decided that I am a prime person so my dream trio of primes are 35L, 85L, and 135L. I picked up a great condition used 85L and was immediately drawn to the heftiness of this lens!! It is quite a chunk of glass. I find that while the AF is slightly slower than the f1,8 version, it doesn't bother me at all! The quality just exhudes from this lens.......contrast and colour are the best I have seen (and yes, I have owned a 135L). People often describe shots taken with this lens as magical and once you start using it, you quickly realize what they mean. It is as good as you read about..........
The one thing I must mention with the 85L is that there is a learning curve in getting consistantly good shots with the very narrow DoF wide open and even stopped down a bit. I am still in the learning mode but that is half the fun! It is a fun lens to learn and when you do get a great result, it is well worth the expense. Highly highly recommended!!