I wouldn't want my opinions to put anyone off trying it for themselves, though.
George - I've still got about a tablespoon left, in the original bag which Terry sent me. I can send it to you if you like, so you can compare it for yourself. Perhaps Terry's offer of a free sample for anyone who PMs him still stands. Some people might find it improves their curries, to their tastes.
I certainly don't think it's any kind of 'magic ingredient' though, and while there may be a slight aromatic difference to Rajah Mild Madras, they definitely smell like they're both from the same 'family'. TRS Madras mix, on the other hand, smells markedly different.