I've used both in 20" on my folder. The bike does mainly tarmac, but also I ride it on my training rollers. The Big Apple I found comparatively heavy and slow(er) . It gives a less harsh ride but I didn't like the things much. I'm about the only one, they're highly rated for comfort by many.

I have Marathons now - not the Marathon Plus which is heavier, and I like them for their quality ride and acceleration. They're good on the rollers too, but I keep them at 60 psi, I prefer speed to comfort. I've not had any puntures yet. I have Conti Sport Contacts on my other bike and like those too. YMMV!