We went to Salzburg for a weekend, 3 adults. It's a very quiet city and we enjoyed wandering around. We saw most of the sights on the first day, and was glad we didn't pay for a tour. It is a very simple city. Locals were a little impatient and not as friendly as I was expecting (but again being Irish friendliness is 2nd nature)
I have to be honest having also spent weekends in Rome and Copenhagen recently Salzburg did not compere. If quiet and chilled is what your after this will be perfect. If you want a 'buzz' and to fall in love with a new city I doubt this is the place.
I'm conscious that march may just be a quieter time for tourism , so something to consider.
Food very plain and relatively good value.
Alcohol was inexpensive.
Glad to have seen it, wouldn't be in a massive rush back. Sorry to if that seems harsh.
Oh and beware of airport, once you go through security there is NOTHING!!! (Except for €5 rubbish machine coffees and the worst range of breakfasts/sandwiches ever)