I've started to look into higher definition music and there is a big difference. I've been streaming HDTracks and my response has been similar to your experience with SACD.
Recently I was talking with a Producer / Engineer and he started me thinking about DVD Audio. I don't have anything to play DVDA with just yet, but hear Oppo is coming out with a true 4K player, so holding out for the used BDP105's that are likely to hit the market.