Hey Deb
Yeah thanks for the mentioning Cam. The 100mm f2.8L IS USM Macro is an insanely sharp lens. I want one due to the AF speed as well as image quality compared to that of the 100mm f2.8 Macro USM. I've found that this lens is by far the sharpest lens I've come across by Canon ( well the copy i was using, which was only JUST serviced by the Pro team at Canon, that might have been why). I actually want this particular lens to replace the want of the 135 f2L USM... i know it sounds weird, but in comparison for portraits this lens is awesome for what it is, even if you have the 70-200 f2.8L IS USM II, it does not compare to this lens.
In comparison to the non L series, not only is the AF speed significantly faster, but the IS is far more advanced and the optics are much much better than the non-L. The colors, detail and punchy images are absolutely stunning. There's something about the build that screams quality to me, in the image and in the build. When I first picked it up for the weekend use, my jaw dropped, knees weak and went wow.
If you're considering purchasing the Tamron, I wouldn't do it. I've had fun with the Tamron 90mm, but it doesn't compare, the 100mm f2.8 canon NON L focuses tack quicker making it more versatile as a unit, the tamron also had slightly soft edges, but that might have been the copy i was using.
The only problems that i found with it was the AF back focused alot, might have been my camera though..
The other thing was, the shadows go quick. I had to reduce contrast in picture
styles to compensate for this, don't know how to explain as such, but if you shoot JPG like I do best bet is to reduce contrast with this lens.
CA is under control wide open, can't complain as much as I regularly do ( and Cameron knows I'm quite the pixel peeper). Can't complain
Hope this helps you in your decision, so far the cheapest I've seen it for is
http://d-d-photographics.com.au/canonlenses.htm#100mm28Even the overseas market is $3 more + import tax.
By the sounds of it, you're going primes
85mm f1.2L now this.. haha my what lovely taste in lenses you have.