Well for me, the size fit perfectly.  I can't always just "slip" them on but with a little tug they are on.  I bought them because they are warm, waterproof and comfortable.  I live in the South and was visiting family up North.  I was able to take long walks with dry comfortable, warm feet! YAY.  I will also wear them in the cooler months here in the South.  I appreciated all the reviews as I found them very helpful.  My size is 7.  In some heals size 7 are sometimes slightly loose but 6 1/2 would kill my feet.  So maybe that's why size seven fits perfectly?  Sneakers also fit perfectly in size 7.  Very pleased.