One could argue that Lep's World is actually a pretty good game. Sure, it's no masterpiece, but the bright visuals and simple gameplay are great for when you need that platforming itch scratched on the bus or something.
But, once the real Mario is out there, I don't really see people ever coming back to Lep.
It's kind of a shame, too. With three games and just under 175 million downloads, it seems like they had a little franchise going.