Great replys - thanks for your insights.
I will watch the movie for the second time today. My takeaway so far is that this new version allows Sondheim's lyrics to become a greater part of the experience. I've read his books and am well aware of his criticism for some some songs and praise for others. In the end, at least for me, the purple lyrics actually do fit very well in this emotionally charged script.
Regarding the soundtrack - which is what I asked about - I agree completely with the comments added here. It is a sound which is particularly rewarded on a great sound system.