CVT Transmissions. Pros And Cons ?

Hello,

I have always had cars with automatic transmissions.

If I remember right, only some of,the Nissan's had a CVT type in the "past".

Now, two cars that I am considering apparently have CVT type.
An Accord and the Subaru Outback.

Know nothing re CVT transmissions.

Might someone please outline for me the pros and cons of a CVT vs the regular kind of transmission.

e.g, reliability, smoothness in shifting, etc.
Why don't all cars of this size use fhem ?

Thanks,
Bob