Outer ring - who uses and what are your findings

I bought a traded-In Merrill-Williams 101.2 with an Ikeda IT CR 407
tonearm. I believe that the 101.2 is designed to be used with a centre weight and ring. The 101.2 came with the centre weight but not the 
peripheral ring. Curiosity got the better of me and I bought the,
quite expensive, ring separately.
I now use the centre weight and ring for all my records. Not to flatten them but because you can hear the difference. Blacker back grounds
and more recorded 'ambience'. Slightly more very low-level detail.
I do have to take more care when cuing my Ikeda 'Kai' but think It's
worth the effort. 

I use the VPI ring clamp with my Classic 3. It does seem to help flatten out slightly warped records but honestly I don't hear much of a difference with it. It's also a PITA to get installed correctly on some records as it can slip off an edge. I'm not sure if it's due to variations in record diameter, record thickness, or possibly slightly off-center drilling but whatever the cause the outer ring can wobble slightly if it's not sitting perfectly. That can't be good...so is the cure worse than the original symptom?

From the sounds of things I will stick with my Mitchell center clamp and just avoid buying badly warped records!
I have none in my collection that I deem bad enough that the Mitchell does not resolve, maybe I am lucky.

I have two systems of hold downs in my tables, one a screw on clamp on the TNT - I've avoided trying a periphery ring on that table as I believe it requires a change in platter and a $2,000 bill that probably isn't warranted by any benefit in sound. The existing set up is excellent and I'd be reluctant to give up the composite platter I have that significantly benefited the sound.

The other table, a Sota Cosmos, has vacuum hold down with a screw on clamp and it is also very effective at taming mildly warped records.

I'd be interested in doing an A/B comparison on the same table, fitted with a stock clamp with and without the ring.  What have people that have done that observed - any benefit on non-warped records, or is it just useful for the odd warped one?

I also have a VPI with an older acrylic-lead platter that I wouldn’t change. So I opted for a 2.5 lb. 3rd party ring. It is a TTW ring; they’re out of business now, but there's still a reasonably priced vendor..

Not only did it improve the sound and flatten disks, but I find it easier and faster to use than the old VPI clamp. Sold the VPI SS center clamp so the $ burden was eased.

I would not be without the ring clamp. Adds flywheel too.