I totally agree with jpatokal, and since you are traveling with a group you might be able to obtain an upgrade to one of the suites for yourself (business is not exactly booming in Jordan right now, although an improvement from last year). Taybet Zaman is on the site of an old Ottoman village, so rooms are in what used to be village houses, all renovated very tastefully with period furniture, local handicrafts (carpets, pottery, wall hangings) etc. Even some of the the bathroom amenities are made with local products (olive oil soaps, Dead Sea salts....). Having breakfast al fresco on the outside terrace, looking at the gardens and listening to the myriad birds is quite an experience.

Petra IS a fantastic experience, and you need to spend at least two days there to really see all the sights (can get quite tiring under the summer sun). Since you will be in the area you should also definitely see Wadi Rum.

Oh, and do spend one day at the Dead Sea on your way to or from Petra. The Movenpick is wonderful.