Stylistically it's similar, but The Leftovers is much better than Lost, imo (and I was a pretty big fan of Lost). It's been a minute since I watched the Leftovers, but there's not a bunch of dangling unfinished story threads hanging all over the place, like Lost, if that's what you mean.

There's mystery that's unexplained sure, but not a ton of loose ends (that I recall).

The Leftovers is among my very favorite shows of all time.