What's the best program to use ?

Well, the question is: I started making a mission with the OPT, after that, I mix it with FSX Mission Editor, an now I've seen that there is another, called Instant Mission Maker, with beautiful screenshots like displaying objects, etc. From your experience, what is the best of them ? ( Or a combination of them ?
IMM looks nice and easy to use, just watching the videos here

problem is, i can't find a free demo version of this to download so i can't tell all the features. can someone familiar with it tell me if it has the tools to create a red bull like race circuit, complete with gates, timers, scoring, etc?

thx steve