The two kings of the ring; in their respective disciplines.
Here's a head to head of Marc Marquez and Valtteri Bottas going head to head at the Red Bull Ring this year.
Bottas set a blistering lap record of 1.04.25. Marquez set a not so paltry 1.23.23 (contrary to what the video says) - a whole 19 second difference.
Likewise with the formidable feat Marquez achieved, breaking the 2 minute mark at Silverstone this year with 1.59.94; compared to Lewis Hamilton's 1:30.62.
So to answer the age old F1 vs. MotoGP saga: F1 will always win. This is due to double the amount of wheels and brakes meaning increased stopping power, a much larger wheel footprint thus increasing cornering traction and stability combined with F1's aerodynamic capabilities and down force leads to abundantly faster corning speeds. It's not difficult to see why F1 machines are faster. The only weapon the Grand Prix bike has against the "car" is it's launch, acceleration and straight line speed.
But I ask you, what's more entertaining to watch? I guess the answer to that is subjective.