I have an older one in Nikon mount but seldom use it as it is an AF lens. I use even older manual focus macro lenses for my macro shooting as both AF & vibration reduction are of little value when shooting life size. Now if I didn't have other lenses to take care of other scenarios (like portraiture), I might have used it more. Really, you can't go wrong with any "true" macro lens. They all deliver as long as your technique is good. The major differences will be in build quality & additional features (like AF, VR, IF and focus stops). Yes, some may rate better on bench testing, but real world shooting is a different animal. Few, if any, can duplicate bench test results...

The end game of "Backward Compatibility" is playing out for Nikon, and to an extent for Canon, too. While Nikon has done an astonishing job in maintaining the longevity of its legendary F mount lenses, eventually technology and innovation and physics collide and make a manufacturer face the existential fact that they must change product specifications to keep current with new and, as in SONY their Sensor Vendor, disruptive Competitive offerings.

Canon "bit the bullet" and dropped their old FD, etc. mounts and introduced the EF and later EF-S, etc. Mount lenses for their EOS line of cameras, they benefited in the market and with functionality. However, today's Interchangeable Lens Camera Market for Enthusiasts and Pros is now officially disrupted by the A7RIII. I say this, as an enthusiast, who bought a DSLR in October, and a long time Canon EOS user. The convincing events were the SONY introduction and the beyond ORGASMIC reviews given to the A7RIII by the talking heads, both bigoted, and cooler.

I'm all for fantastic new products that take the state of the art and Image Quality to new heights. I can only think that the 30-or so years of Canon and Nikon essentially controlling the SLR and DSLR markets and adhering to their "Backward Compatibility" lens policies to protect their users'--like me--investment in compatible glass. However, as a Computer Industry veteran, where the product cycles from intro to replacement to unsupported spans three years it is a miracle that they survived with this Tactical substitute for Strategy for so long.

HINT: Look toward the US Defense Department Procurement rules that mandates that new Aircraft and Ships and other weapon systems be fitted with Electronics and "proven" Computer Systems. The unintentional consequences that policy is that by the very product cycles built into the technology they will be obsolete and not commercially (DOD Handcuffed support, yes, and a big $$ price) available and supportable by the time the first production (probably Prototype) rolls out.

Nikon and Canon and others, as well, have had these super full frame products ready to roll out for a while. (I already posted on Cannibalization.) The market question for them is will they be good enough to compete with SONY, especially if the users have to replace their legacy lens inventory. And, the challenge for SONY is to manage an ever more impressive Lens Offering with System Components, and more reasonably competitive prices. The 400mm 2.8 seems to be getting kudo's on quality.

The overall message, is nobody controls the market forever. Those Manufacturers like GM, IBM and, perhaps, Microsoft might learn from the Canon-Nikon (and the many before them) controlled market currently being disrupted by a major vendor, SONY and Consumer electronics and Industrial giants, Panasonic, Fuji and our friends at Olympus.

It will be fun and instructive to watch. Hopefully Industry Titans in Training are watching and are not too arrogant to learn.
C