What sort of stuff you going to be using it for? Thats not really a 'true' macro lens, as it doesn't do 1:1 magnification. What sort of budget are you looking at? Ive got the Sigma 150mm f2.8 and I love it to bits. If thats a bit too expensive, then you could also look at the Sigma 105mm f2.8, which lots of people swear by. Also if you are going to be using it purely as a macro lens, then I would say a prime lens really is the way to go. The increased sharpness gained from it being a prime lens is very usefull for macro shots, and I can't see any benefit from having a zoom macro lens.