Vista and above, they are truly impressive speakers. Source didn't impress me much.
I recently auditioned their Spire driven by a NaimUniti (not a typo, this is how its spelt). Highly transparent speakers, well suited for Classical music. IMO, it came close in performance to Kharma Ceramique (best speaker for classical, IMO), which is 3 times the cost of the MLs. No crossovers for most of frequency range, so sound is pretty clean and coherant. the only negative which I felt was a lack of full bodied sound, which is present in conventional speakers in similar price band.
Anyone lookin for speakers in the $10K+ budget should have MLs in the shortlist.