I wouldn't call this a review so much as an impression, but I'll share my thoughts anyway.
The complete soundtracks for the trilogy are the only DVD-As that I have, but the sound is amazing. I have a number of classical SACDs, and they're great, but the LOTR complete recordings are I would say a level or two above any of the SACDs. Not in a gimmicky, show off the surround recording sort of way, just totally like being present. I'm a classical musician (not a good one, but I've spent my time on stage), and recreating that experience is pretty important but all too uncommon. These recordings do it the best though.
I guess the reason I don't have more to say is I haven't listened to them all that many times since I haven't had them all that long. Maybe the OP or anyone else has more to say.