Compared to my s6 edge it seemed narrower and longer , looked like a chocolate bar.
Was worried the s8 plus may look too big. Does it come across as a regular sized phone? (Not into phablets, notes etc)
Which do you have?
I killed my HTC 10 and I sold the replacement HTC sent me. Using the s8 at the moment. The size is good for my smaller hands but it doesn't have a nice feel in the hand like my HTC 10 and other phones. It's almost too thin.
I've seen the s8 plus in hand. Doesn't come across huge like other devices do.
Best bet is to handle each in the store and then decide.