When we removed the old tiles, there was a very ugly crocodyle style vinyl linoleum green khaki in colour and textured. That old linoleum was very smelly and horrible dark. I guess at the time they didn't have too many choices.
My husband removed it and used Ditra membrane to set new tiles. The most neutral color beige 13x13. After he left the thin set for the membrane to dry there were some botches. I talked to people at the tile store and they told me he should have removes as much glue as possible. Fortunately the tiles weren't too big so we still could set them, but in a couple of places as well as junction with kitchen tile there are level differences in a couple of spots. Also the transition to the powder room has a too big for me anyway grout space.
In a bigger space it is a bit more difficult to keep everything leveled. It still looks good. I used mocha mapei grout.