It depends. It's a preference thing, some people love them, some people hate them, and some people, like myself, go back and forth.

I agree with DX-Man though, it's not so much about push-down/pull-up, but being attached to the bike. I also think it's easier, but I tend to cheat the bike into the air with clipless pedals, so I do try to mix in platforms to work on technique.

Clipping out is more intuitive than you think.