Do you shoot much with the 85mm f/1.8 USM? What about it makes you want to upgrade to the L? I haven't shot with the 1.2, but I love the 85 1.8, and I have read posts from many who have used both who still like the 1.8. Not saying it's better, just that maybe upgrading a different focal length first (like the 135) would be more beneficial.
I picked up the 85mm f/1.8 about 2 weeks ago... so I really haven't had an opportunity to run it through its paces. I actually wanted it more as a portrait lens for when the baby finally arrives. Something sharp... nice shallow depth of field, etc.
No baby... no subject other than dolls... and that is a touch boring. I looked at the reports, and I know the f/1.8 is really really nice and it basically compares with the f/1.2 at almost all apertures. So is it worth paying $1500ish for a stop of light, slower auto focus, and shallower depth of field. Kinda. I won't make money off the lens, but if I have it for 3 years and I sell it for about what I paid for it, then it will be like I rented it for free. The money is in an escrow account and I can tap into those funds whenever I want.
I am not mesmerized by red rings (I'd never even consider a 50mm f/1.2L or a 17-40mm f/4L), but I can respect the fact that some of the lenses are that expensive for a reason. That is the same reason they hold their value well.
I appreciate all of ya'lls help... but I'm not sure that I'm any closer to making a decision on the matter.