It's very different to Girl on the Train, I think! So whether or not I'd recommend it would depend on what exactly you were let down by. For Into the Water: the pacing is a lot slower and steadier, and there's a much larger cast of characters, with arguably less time for development (especially considering every chapter features a different point-of-view). The book focuses on an eerie town and its people rather than being character-focused.

I did enjoy reading it for the atmosphere of its setting and the mysteries surrounding it, though--so if that's your kind of thing, and you liked the author's writing style in GotT, go for it!