The two main sites of interest are the amphitheatre and the citadel. You can pick up a guide or go at your own pace. There are plenty of information boards so a guide is not essential. The amphitheatre is large and spectacular. The citadel has amazing views over the city. If you don't know where to go it is a useful tour. If you only wanted to see the Citadel from which you can see the amphitheatre, this could be done by just hiring a taxi. The shopping place i went to had the best souvenirs that I saw anywhere in Jordan. If you want souvenirs this is a useful tour.