Compared to Formula 1, where sometimes the only passing takes place in the pits, passing in MotoGP can take place anywhere, anytime.
Add to that the fact that there is no dominant force in the series, and your have a very open competition, which makes for great racing and great watching.
This variability is compounded by the great tyre war between Bridgestone and Michelin. What this means is that certain teams will do better than others because their tyres perform more consistently at certain circuits.
Take the first race for 2008 for example. The season starts at Qatar, and will be held at night, for the first time. Night racing means lower track temperatures, which affect the performace of tyres.
Qualifying results show the tyre factor at work. Most of the top qualifiers were on Michelin, with Casey Stoner (current world champion) the exception, qualifying 4th on his Bridgestone-shod Ducati.
It should be a great race to watch, with new riders arriving at MotoGP (Jorge Lorenzo qualified 1st, with fellow debutant James Toseland at 2nd) and also new bikes, which will hopefully show which manufacturer has stolen a march on the competition during the winter break.