I've got 9 macro lenses from 55 to 180mm in focal length. Some are manual focus, others are autofocus. They span Nikon, Tamron, Sigma, Vivitar et al. Optically they are all good. Sure, some optical differences might be detected when doing a bench test, but not so much in real-world shooting. I'd suggest looking for one with the features you want rather than brand name. The 90-105 range is the best compromise as they allow a bit more distance from the lens to your subject when at life-size... As you get closer to life-size, the usefulness of AF and vibration reduction become lessened. That said, those features will be better suited at normal distances. Personally, I use an older manual focus 105 as my go-to macro lens. Samples can be viewed on my Flickr stream...