it's a great product that removes teh certainty that a creature with a move of 6 will always always always catch a creature with a move of 5. However I've found it does have the potential to bog down what should be a very exciting scene if you adhere too closely to the options provided.
I moved the system over to 4e, and kept the basic mechanic of abstracting movement/distance, and also of applying penalties for attacks made at various distances. For terrain or surface I apply across the board penalties, and for differences in movement rate, I give each participant +4 for every square of movement they have over their opponents. This makes slow effect brutal.
I wing most of the other actions, such as barnstorming, damn the torpedoes, etc, by offering choices to the players and then assigning DC's to various skills based on what makes sense: endurance to smash through a fruit stall (comes up a LOT), acrobatics to parquor over an obstacle, etc.
I also kept the assumption that everyone is double-moving; if you use a standard action for anything other than movement, you fall back one range increment. vehicles are slightly different, but the principals are the same. I use acrobatics as the driving skill.
Finest moment: team was in an animated carriage going to a site to investigate. When setting the scene I described a tired mule standing near the road. Later, when they were fleeing with hell demons behind them, the mule was in the middle of the road. They avoided it by smashing through a garden wall. Great fun!
--Z