When I bought a copy of sonar at gc the guy behind the counter looked at the box and said "wow... That's cakewalk?" With a puzzled look on his face. Pretty funny... And speaking from the perspective as a former gc salesperson (22? Years ago) if we can sell the more expensive product we will.
GC here in sf has some good people in the pro audio dept but I would never go into it blindly. Always build a relationship.
That being said, i would take Craig's advice and demo other programs as well. One thing to remember is that many midi keyboards come with lite versions of ableton live that you can try.
Sonar is a joy to use and very intuitive. Not mid-level at all. There should be a demo soon as well. The upgrade price can't be beat. Since you've been using maschine studio, bear in mind that the creation process is significantly different but not so much that you'll get lost.