As far as using one for just a play through, I'd honestly pick Leaveany. It's better at dealing damage I think. It has two stabs, learns both leaf blade and x-scizzor, both very capable moves for its stab. Leaveany also get's swords dance, while it isn't as good as quiver dance obviously, it's still worth mentioning.
I've used both in my playthroughs of White version, and I was happier with Leaveany.
Just don't send it out against fire and flying pokes....ever....
For going against other players, both are pretty bad tbh, but lelligant wins just because of less weaknesses really.