Then I recommend that you borrow/rent the lens to see it for yourself. No one can be a better judge then yourself!
It's probably better to borrow the lens for a field test.
Might be a bit too slow for portrait depending if your subject moves..but for macro, the amount of details is simply superb for its price. I like it very much.
Hi SK1968, can you elaborate about it being too slow for potrait? Or were you referring to fast action stuffs (sports)? I used it for potrait with no problems.