I really like this Simulation too. In the past i had the old Shuttle Sim from Virgin and i was pleased when i discovered SSM2007 this summer. The Copy Protection didn't cause any problems so far although it is a bit disappointing that i cannot run it on my notebook because of the way it works.
EVAs are a bit tricky but the new updates makes the sim are a little bit more forgiving when it comes to reach the correct position for making the next step in the mission.
I played all missions up to STS-93
http://en.wikipedia.org/wiki/STS-93
which is a nice mission to relax and do some sightseeing in camparison to the former tougher ones
.