As mentioned, many clever platforms have clever feet as an integral part of them - HRS and Townshend products obviously apply. I can envisage that in some cases adding extra layers of isolation not intended by the designer or removing those feet may confuse things.
I think that that sort of ‘suspending your suspension’ issue is why both @916SPS (Hi Pete!) and I have found the best sound if the feet of our LP12s sit on something rigid, without Nimbus assemblies or some other clever feet to support the LP12 directly (i.e we don’t by-pass the Linn feet). Those with unsuspended decks may well conclude differently.
I’d also be surprised if adding a different company’s feet under (say) a Zazen or Pro-jekt platform was an unalloyed success, though I’ve been wrong before. However, if your isolation platform is (say) a chunk of maple or slate or granite (or at the other end of the scale Torlyte), I’d expect it to cope with some frequencies much better than others, so clever feet optimised to address a different issue from your platform’s forte would be well worth investigating.
In an ideal world, a few of us could do the experiments and give a definitive answer for everyone. However, there are many variables here (starting with how good your ears are, how much you notice small differences, how loud you play music and so on). Thus, even if we all had the same boxes, rack and living room (probably the most obvious variables), we would still probably disagree on what sounded better, by how much, and what the difference is worth in £.
Given that, trying one or two options yourself unless everything (including room shape and the listener) are in every sense pretty standard makes a lot of sense.
I am still surprised that so many here have simply found something that works (and in the case of all the Fraim-users in particular I’d accept it is one that works well in most situations) and then never questioned whether it could be improved meaningfully. We don’t do that with speakers or speaker cables or power supplies for streamers…
Do let us all know if and when you reach more conclusions.
Finally, I have been thinking about the smell issue you raised. My own experience is that some isolation (e.g. HRS plates more than the Nimbus feet) seem aimed at just the sort of vibration that hifi boxes get when sitting in front of the speakers - so, the louder the music, the more obvious the benefit. Doubtless, there will be other sorts of vibration that excite things in much the
If you gently vibrate a dusty old transformer, you presumably shake off some of the dust. The less it vibrates, the less dust gets released. Is that perhaps creating the difference in smell?
Of course, there is an entire school of thought that contends that all this is irrelevant because a box with no moving parts (apart from electrons) cannot possibly have performance affected in any way by isolation from vibration. However, my ears disagree, and so (presumably) does anyone who owns an interconnect cable with floating pins.