I have an Ayre K-1xe and I think it is fantastic. I also think Ayre gear pairs especially well with Avalon speakers. It's highly resolving with a great soundstage. I don't know how it would pair with Krell but I suspect well. I haven't heard the MBL. There was a K-1xe on here that was still available the last time I checked for $3900. That's underpriced so you could buy it and re-sell easily. Maybe consider trying both and re-sell the one you don't keep?
