Power Amp advice

I have heard Ayre and ML, but not Rowland. But based on what i have read, and the fact that you seem to like Rowland...i do think the Rowland is a very good choice. By many accounts, they make good quality stuff. As for brand matching, many people i respect do like matching pre and amp. But not everyone. Many people like tubed pre with SS amp...which generally means different brands (though not always). I do this and love it.

One thing i have read is to be careful of service with ML...seems like due to change of ownership, servicing products that were not sold by current mgt is not always so good. is 532H current?

Did you keep your Rowland? be interesting to see which you prefer with new Rowland amp. In any event, goodluck.

there are levinson 436 monoblocks for sale at reasonable prices; a 334,335 amp would also be a good choice. IF you wanted to stay with ML. I would love to see a review of the ML-532 stereo amp as well- i would have to say that just from looking at it it's either a waste of money or it's one of the best stereo amps out there. as for the very latest amplifiers from ML they have gotten some favorable reviews but i am not aware of anyone comparing them to the Iron-Giant gear from a few years back.

I use this Mark 326s preamp with 201 power
amp

Well, mixing oil with water was never successful.
I would recommend to go for Corus Rowland Preamp instead of the 625.

I use Parasound JC1's with a ML 326. Fantastic combination.

Of those you listed the only one I'd consider would be the Ayre, but I'd still choose my JC1's over it.