I believe both work with 2010, but I may be wrong there. NASSP and AMSO are two different types of simulations. AMSO is more 'flashy' i.e. it has better models and visuals, but isn't very realistic (well, it is, but not as much as NASSP). NASSP is a true apollo simulator. If you want to fly that, be prepared to read manuals, and lots of them. If you are new to Orbiter, I suggest AMSO, but if you are familiar with it, feel free to tackle NASSP.