Is the PS audio M1200 D class amp worth buying or should I stick to A/B class mono amps

I've had the PSA S300 6 months and it is a great sounding amp. The VTL ST150 needs re-tubing and that costs almost what the S300 did, on sale. The highs are smooth and the bass is so much better controlled. Enjoying the S300 a lot. So much so I have another brand class D amp on the way.

Thanks,

aldnorab