Hi Julian
I'm very pleased that the old Pioneer is still going strong!
I've tried the (now obsolete) Jelco SA-750D, the new Jelco TK-850S, SME 309 and the new Glanz MH-94S on the GR. The Glanz is utterly extraordinary, as it should be at over £5k, but of the others I prefer the TK-850S, which has a more 'grown up' and musically expressive character compared to the old SA-750D (which has been reborn as the cheaper Jelco TS-550S) and seems, to my ears, to play music better than the SME. I don't really care for the SME 'sound', even though I admire the engineering and quality of their products, but actually the engineering of the new Jelco is pretty much on par and I do genuinely prefer the sound of the Jelco.
Your mentioning SME has reminded me that I must find a new home for the 309!