Ben cotto, or ben cotta, is an Italian word used to describe well-cooked or thoroughly cooked food. (It's not used to describe mushy pasta, just your regular soft pasta.)
Al dente is an Italian word used to describe food, typically rice or pasta, that is cooked so as to be still firm when bitten. (Perfect pasta is firm on the outside and tender on the inside, which is al dente pasta.)
Which tastes better? That will depend on the sauce and pasta types. Ben cotto the long and thin ones with watery sauce is fine and goes well but ben cotto the short ones? HERETIC
Also, al dente pasta has a lower glycemic index than the alternative because it takes less time to cook.