'Diminishing returns' is always the issue in this hobby/industry/obsession, of course. But the same applies to everything. I have two turntables. On one of them I have an AT OC9XML, on the other an AT 50ANV. At retail prices, the Anniversary lists at about three times what the OC9 costs. Is it three times better? No, it isn't. Do the differences warrant the cost? To my ears, yes. It's that last touch of delicacy, the slightly better rendition of high treble, the cleaner separation of instruments, etc. If I had just heard the OC9 then I would have been perfectly happy. Having lived with the 50 Anniversary, I am aware that it is better.
The Audio Note is no different. Is the Silver Signature version twice as good as the standard? No, of course not. However, it takes what the standard version does and simply expands on it in pretty much every way. The components (and cost thereof) are a red herring really. It is better because of the differences in components, but it is the sonic differences that matter to people like us. I put more than once in the review that the 'standard' Meishu is superb and I would be very happy with one. The Silver Signature is just 'more of the same', but having heard both, and very extensively now, if the Silver Signature was financially possible, one would be in the rack here.