A few thoughts: Proud owner of one of the most famous plot twists of all-time, this is one of those gateway horror movies that was just too creepy for mainstream (and unsuspecting) audiences of the time, leading it to be considered a much more frightening movie than it really is. But it's still a really solid and occasionally chilling drama, with some career-best performances by Bruce Willis, Toni Collette, and (of course) Haley Joel Osment. Though the twist and certain moments don't hold up too well to scrutiny, this is still a very clever and competent script with great cinematography and an incredible musical score. James Newton Howard always elevated Shyamalan's films, and this was one of the best examples of that. It didn't just rely on jump-scares to be creepy, but built up tension through well-constructed scenes that allow the performances and music to suck you in. There's definitely a bit of that wispiness that would take over his later movies, but it doesn't get in the way of this fantastic drama with some genuinely creepy moments.
Who would I recommend it to? Pretty much anyone. This is a little too scary for youngsters, but if you can handle a little horror, this is still mostly a drama.