I've never been able to get along with Birkenstocks, they are comfortable but just do not suit my feet at all, try as I might to like them.
I bought my first pair of Birkenstocks when I worked at summer camp in upstate NY years ago & everyone was wearing them....and I've bought them several times since.My daughter loves them & now that we're just about the same size, (give or take half a size), she has inherited several pairs of Birkenstocks....plain, floral & a patent orange, her favorite.
Which leaves me with a gap in my beach footwear wardrobe!
FitFlops have been around for some time & I know many people love them.This summer their styles have evolved & I have seen several people wearing them....and I didn't recognize them as FitFlops, which I have to admit I wasn't too keen on at first.
I like the slight wedge of the heel & they are super-comfortable, just the thing for the warmer months, particularly if your summer involves a lot of walking but trainers aren't your thing.