Originally posted by stevebrot The working distance for 1:1 is the same regardless of crop. What changes is the FOV at 1:1.
Thanks for pointing that out!
Still, on APSC you get a different FoV, one that gives an apparent "boost" to magnification, and this makes 70mm macro, even 50mm and 35mm macro, much more reasonable on APSC.
Anyway, back to OP: Yes, Sigma 70mm is great macro and if you can find it, you will most likely enjoy it, whether on FF or APSC.
You also have plenty of alternative options which are easier to find, like DFA 100mm (and its previous versions), Pentax DFA 50mm, Sigma 105mm, Tamron 90mm.. none of these will disappoint you optically. They are all pretty great, and come at a reasonable price, considering how great their rendering is. I have not seen any forum posts where someone would complain about one of the modern 1:1 macro lenses