Both GREAT boats. Each with their own strengths and weaknesses. Sadly, in the boat selection process, there is no holy grail of the one perfect design.
We had a cat and were happy with it. We're back to a mono now because of haul out
issues and the constant climbing of steps. Paradoxically, we did more up and down the stairs in a cat than in a mono. Murphy's Law dictated that whatever we needed was always in the opposite hull
As far as beaching a cat? Only in the sales brochures, or in desperation. You need that "perfect" beach and a decent tidal range and you must love racing
the clock. It certainly is possible and people do it, but surprisingly few.