T.D. - since you mentioned Heidsieck and were looking for a more eccentric set this is definitely one that is at the very top of my list in interpretation.
I was not that impressed with Pienaar, his interventions don't bring anything new to the table for me. They seem superficial and done for the sake of recording a cycle to be different. Whereas Heidsieck and Sherman's usually (more below on Sherman) sense.
I'll copy and paste what I posted to GMG after hearing Sherman's cycle:
I've now made it through Russell Sherman's cycle. I remember hearing it a while ago on Tidal streaming, listening to it in order and immediately being turned off by it as at least for my tastes the Op. 2 sonatas were really, really off putting to me. And then reading one of Jed Distler's reviews where he gave one of the discs a comically bad 2/10 rating; it just didn't have me interested in hearing more. I am sort of puzzled why Jed Distler felt the need to slam it to that extent when he often extols the virtues of Schnabel.
Fast forward to a few weeks ago I came across these for cheap and then decided to complete the set. Besides the Op. 2 sonatas which I'm still not a big fan of I think this is an extremely interesting cycle. Sherman's tremendous dynamic range, tonal color and his obsession with really bringing out the voices makes for a very interesting non-reference cycle. If you can look past his sometimes reckless use of rubato, tempo stretching, the little pauses he takes, etc. What I have founds helps is "listening to them from afar" instead of honing on these things, with that frame of mind Sherman has some tremendous ideas. This will be one of those great cycles I'll be enjoying for years, I think the way he breaks up the sonatas by volume was very well done as this isn't a cycle I'd want to listen to from start to finish but instead focus on in the order he presents them.
These were some sonatas I listed after someone asked for some recommendations:
The Pastoral Sonata is a real high point. Others are 10/3, an unusual Appassionata, 109 and Op 90. Op. 110 is also good.
If it came down to a choice between Heidsieck and Sherman it would be a tough choice. Sherman has more sonatas where he goes too far with his idiosyncrasies like the Op. 2 sonatas, in that regard Heidsieck is more consistent. Heidsieck's recordings of the final 3 sonatas are also some of the finest I have ever heard (along with Lucchesini's).
Either way these are two cycles that I absolutely would not want to be without and will be enjoying them for decades to come. Jed Distler trashed one of Sherman's volumes and it's one of his reviews I feel could not be further from the mark.
Since you mentioned Jed Distler in a later reply, I have found he writes in a strictly objective style. If you play piano you will immediately understand what he is saying. I want more than from a reviewer; tell me about the pianist's realization of the works, their insights, their "depth" of interpretation (sorry hate to use that word). Having said that I find his tastes lean from the conservative to the ultra conservative when it comes to interpretations. I'm often left scratching my head in many of his 8-10/10 artistic quality ratings that are nothing more than fairly straight forward, very well played recordings. On a true scale of 5 being average I would be marking these recordings far lower. Truly great interpretation goes beyond merely playing the notes at written tempi markings, accents, etc. Even something as simple as allegro con brio appassionato should tell an interpreter that much. Fortunately most of the great pianists know this already.