I'm reviewing the 512 at home now as a potential upgrade from my ML390S. Wasn't really impressed with the sonic improvements, considering the cost, until I also upgraded my speaker cable from Gryphon blue to Nordost Valhalla. Also upgraded to Nordost power cord for the player as it made a discernible improvement to clarity, dynamics and soundstage; although the main gains in this area were provided by the Valhalla speaker cable. Comparing the 390S and 512 with the cable improvements in place for both is like chalk and cheese, or more appropriately, recorded and live. Redbook recordings took on a palpability, clarity, spaciousness and dynamism that is breathtaking at first hearing. SACD is the same but more so. In comparison the 390S sounded rounded and muffled, like listening through some kind of padded earmuff. The 512 sounds drier than the 390S, which sounds positively warm by comparison, however having attended a live orchestral concert only last night there is no doubt that the timbres the 512 produce are more accurate. As usual, a disadvantage of the 512 is that bad recordings stand out more while good recordings sound even better. Having said that the Led Zep remasters that sounded way too bright on the 390S (before the cable changes) sounded more bearable on the 512. I listen mostly to classical music, rock, contemporary folk and some blues. All good on the sound front then and convincingly much, much better than the 390S. The bad news is that the 512 error correction allows scratches to voice, that is scratches produce pops and cracks not unlike static discharge - very annoying! Also on one occasion the 512 simply stopped working in the middle of a track and went into standby for no apparent reason, it later replayed the same disc without problem. I should mention the demo 512 has something loose in the case which you can hear moving around if you tilt the case. I gather it came to my supplier in that condition. Whether this has anything to do with the above problems is impossible to say. Will probably not proceed with the purchase - given previous reports of unreliability who needs irritating problems at the price of the 512? A great shame ML can't make this a reliable unit. Will keep the Nordost power cord and speaker cable however.
Remaining parts of the system: interconnects are Valhalla driving ML33Hs directly from CD player. Speakers are SF Stradivarius Homage.