are they better than pbt keycaps??
Is a Ferrari better than a Lamborgini ?
Is a Boeing 787 better than an A380 ?
Is an Intel CPU better than an AMD one ?
You will never have a definite answer.
Anything has pros and cons
Double shots have a better contrast and often larger better looking fonts, and they also have the nostalgia feel that most users like, PBTs will keep the texture for longer time because the harder plastic, and the tactile feeling is less sticky than ABS keycaps.
Both of them are way better than the cheap pad printed ones, like the default Filco keycaps.
So It's just matter of preference.