I bought two pairs of these slippers.  One Medium (6 1/2-7 1/2) and one large (8-9).  I usually wear an 8-8 1/2 so I figured the large would be fine for me.  Wrong! These slippers are huge and floppy!  So I tried on the Medium ones that I bought for my mom and they're too small.  Not sure what the deal is on the sizing with Acorn.  But it seems to me that they need to make an in between size that's a 7 1/2-8 1/2.
The slippers are extremely soft and cushy...but I don't know if they're soft and cushy enough to warrant flopping around the house in them.