KEM cards
 

What's the difference from these and normal playing cards? Do they last a long time? Are they worth the price?

One word -- plastics
 

KEM cards are plastic. Personally, I'm not crazy about them, as I find them a little slick to the touch. The big appeal is that they last a long time. You can learn more here

Personally, I love them. They don't wear out as fast as Bicycles or Bees. You can bend them any which way and they'll stay straight as ever.

There are downsides however. One, since they're plastic, if they get old they can actually become brittle and break. Two, depending on the humidity, they can acquire somewhat of a curvature and become a bit difficult to deal with.

On the whole though, I prefer them over regular style playing cards.

I used to favor playing with KEM cards because of the smoothness, they slide over almost any surface. But now for some reason I really don't like the feeling of them in my hands. They just feel a little flimsy to me compared to Bees or Bicycles.

Yeah I hate the feeling, but I still have a set from the 70s that was passed on to me, and they are in top condition. I generally play with Bicycles though, so I would say they are worth the money to own a set, but never play with them ;)