I've been using i3 for a long time. It's extremely practical while still looking good with relatively small amount of effort, it has sane defaults IMO and it's utterly stable. If you really want window margins, you should probably look elsewhere, though - i3-gaps works well, but it's really annoying to update it manually every time there's an update for i3 (I don't think window margins are worth it, though, they just waste so much screen space). i3 also doesn't support Wayland.