I bought this from Amazon a few months back. It is far quicker to put on than changing to a macro lens and cheaper than a decent one and of course less kit in an overfilled bag.
However its no good pretending you don't get huge DOF problems as in real macro and for best results on very small objects eg v.small wildflowers, best used with a tripod, can be a mini. I use it on Nikon 80-400VR, an old lens which needs switching to over-ride auto-focus with manual; would be better still on lens not needing that.Focus distance around 500mm. On larger/moving things, eg butterflies, pretty good hand held. On normal size flowers, better to use a closer focus normal lens (in my case 18-135) with smaller min focus distance