I had use of an 85L II for five days last year. My best advice with regard do that lens is this: Don't try it if you don't want to buy it. As the saying goes "A luxury, once sampled, become a necessity." Longtime readers of this thread might ave seen some of these images before:
The 85L has a number of downsides besides cost. It's gigantic, massively heavy, and both its objective and rear elements are huge and very vulnerable. Were I to shoot with it all the time, I'd invest in a battery grip (seriously the 85L's AF motor sucks juice like no tomorrow) and an UpStrap. The weight does have one odd bonus. It makes the camera so dense, I was able to hold it for 1/13th of a second and get a surprising number of keepers, like this one:
F/1.2, 1/13th (ya rly), ISO1600. It was stupidly dark inside the nightclub.