Sigma 70mm F2.8 DG ART Macro Lens for Canon

Curious if anyone has had any experience with the Sigma 70mm F2.8 DG ART Macro Lens. It has been recommended for black water shooting and seems like a reasonable middle ground between the 50mm and 100mm. Would love to hear how if compares as far as sharpness goes.

Mahalo.

I would  also be interested in. What I learned is that it's one of the sharpest lens ever produced but the AF is not that good (but I don't have first hand experience with it, but I consider it for my sony A6000)

A belated follow up......I picked up the Sigma 70mm and am very much enjoying it. I moved up to the Canon R5 mirrorless and the lens works great with this system.

Leaving aside the sharpness and AF performance, the lens gets significantly longer as you focus close, which makes it generally unsuitable for use with closeup lenses, plus the working distance at minimum focus is only 40mm .   Not a problem for fish portrait work and the like but something to be aware of when choosing a macro lens.