I ran the 3.5 War of the Burning Sky campaign up to 7th/8th level. I am starting it again in 4e with a new group, still in first chapter.

This is a nice example of getting started. Because when the game starts, after some introductory RP, the thing goes all crazy, race against time feeling for a while. So it's more like Jason Bourne and the perceived "railroad" isn't really such at all. Now, if I recall from the 3.x version, it opens up a bit in the early-mid levels. I haven't read far enough into the 4e versions to refresh my memory since then.