As with most things that we review and talk about...
input from anyone not actually having had the unit in their posession, is not valid, IMHO.
Categorical, all-encompassing statements such as that are not valid, imho.
It is certainly legitimate, it seems to me, to comment on issues related to impedance mismatches, gain mismatches, signal-to-noise performance, and a plethora of other technical and spec-related issues, without first-hand experience. Assuming, of course, that the person commenting knows what he or she is talking about.
And in choosing some aspect of a system configuration, it is certainly both legitimate and desirable to have and/or solicit spec-based understandings that will allow potential mismatches to be ruled out from consideration. That will narrow the field of candidates that need to be assessed based on first-hand experience with sonic performance.
I am in essential agreement with Tvad's comments. Although I have no experience with the Burson buffer, I believe that based on technical considerations I can say the following with certainty:
1)For a component with high output impedance, meaning that its output impedance at any frequency approaches 1/10th or more of the input impedance of the component it is driving, the buffer is likely to be beneficial.
2)If the interconnect cables to the destination component are long and/or have high capacitance per unit length, and the buffer has a lower output impedance than the component driving it, it may be beneficial. That can be analyzed quantitatively, if anyone is interested.
3)If neither of the above factors are applicable, the sonic effects of the buffer, if any, may or may not be subjectively preferable in any given system, and need to be assessed by listening.