I stayed there for 2 nights in February 2006, and was very impressed.
First by the location, which is gorgeous. Tamerza village is one of 3 great mountain oasis, and located on an "oued" canyon. From the hotel, you have wonderful views on the canyon and (on the other side) the old (now abandonned) village. The two other oasis, Mides and Chebika, are a few miles away, and both worth a visit.
The hotel architecture and room design reflect the local traditions, while providing all modern comfort you can expect. The staff is both very friendly, very efficient, and will provide very good advice as for hikes and trips.
Last but not least, the restaurant offers local dishes, sometimes "reinterpreted" with a bit of Western flavor, but these were among the best meals I had in Tunisia.
Definitely the best hotel I had during my trip. They are currently expanding the current building, hopefully the "boutique feeling" of the current 65 rooms won't be lost.