I would definitely vote for playing a scenario. Modules are fun, but characters in the middle of them (as ours would be for two weeks) cannot be played in any other PFS games during that time, and I at least will be playing between the sessions.
Also, playing a module this week locks out people who might want to play in two weeks' time, but not this coming Saturday, since the players from the Part 1 would have priority to play Part 2, etc.
Of course, if two tables are available this week and next, then these arguments are moot and the module would work quite well.