5Dmk3 with 100mm 2.8 USM macro, how fast does it AF?

So I'm moving up to full frame. Have a 5Dmk3 on order, salivate. And I do a lot of portraits and fashion photography. Previously I was using a 60D with 50mm f1.4 and the 18-200 kit when I needed reach.

That 50mm on a crop became a nice 80mm. But now that the 50 will be a 50 on my 5d3 I'm in search of a portrait/fashion lens again.

Can't really afford the 70-200 f2.8 right now.  And I happen to love macro photography. So I was leaning toward the 100mm 2.8 (non L) macro over the 85mm f1.8.

I've read the 100mm macro is a tad slow to AF, but with the 5Dmk3 being fast at AF I thought maybe it compensated somehow.

Anyone had the chance to try this out? Thanks in advance.