I used their ephesus tour. The guide was perfect. We were 12 people on that group. I paid 60 dolar more to them then another one but it was realy nice. Asspecialy the lunch I still remember the taste :) Ephesus is the best to see in kusadasi. The agency we used was sisan tours. http://www.sisantours.com you can see some tours in Istanbul also in that page. Enjoy your vacation
dave