Tamron 90 mm macro or Sigma 70 macro

I already have a Sigma 50f2.8 macro, but wanted a longer telephoto. I'd like to use the lens for portraits, some available light, and perhaps some macro.
I like the idea of more working distance, but how much does this matter for the 90 and 70? Also, I would think that the 70 mm focal length on a crop XS would be better for general indoor use than the longer lens.
I am also toying with the idea of getting a Canon 85f1.8 and a longer macro.
What would you do? I don't have a lot of experience with macro photography, but can't imagine not doing it.

artyH,
I wouldn't do anything because I already have the Canon 100mm f/2.8

From the standpoint of doing macro, is the Sigma as good as the Tamron?
Is working distance OK for these two lenses?
Is there any practical difference in image quality?
Some reviews describe the Sigma as sharper, but at FM, some people have reported quality control problems with the Sigma.
I would really appreciate feedback from any owners of these lenses.

I haven't got any first-hand experience with the Sigma 70, but do have the Canon 100, Sigma 105, and a close friend had the Tamron 90. My thoughts on your post are these:

- You want more working distance from your 50. The 90 will give more than the 70.
- The Tamron 90 is very sharp, as are most true macro lenses.
- Not sure about the quality control problems with Sigma, since the copy I have is spot on.
- With the 90, if you put a full set of extension tubes on it, you can get close to 2:1 magnification at reasonable WD - not a bad trade-off.

The above is all macro-related thoughts. As for using the lens for portraits etc, the 2.8 may not be fast enough for indoor shots but depends what you want to shoot indoors. I was at a netball game the other week and 2.8 lens could not cope at all indoor sports without flash.

Thanks for the advice. My Sigma is fine. I may want more than one longer lens - the Tamron looks like a good bet.