If you go to Eopinions you can read comments about RJ. The comments were a bit negative about the service but it's free so who cares.
From Amman you can take day trips to Jerash ruins which are fascinating. Not far is the Dead Sea and a very nice Movenpick Hotel. Then go to Petra for 1 night. From there continue to Wadi Rum (desert made famous by Lawrence of Arabia) and if you like the beach continue south to Aqaba. You can also visit Eilat in Israel from there and Taba in Egypt and continue to Mt. sinai. Lots to see and do.