Have spent time with both (and quite a bit of the models both up and down the lines) and....you have a big WOW ahead! Small Marantz is very warm, rolled off highs with a punchy bass.
Big Sansui is more clear with an even slight warmth but has highs that sparkle out of that and the bass is quick and tighter. (Big Marantz is similar and a wonderful sound too.)
Speaks are going to sing like you haven't heard them sing before! Enjoy