My wife and I found Sasha through Tripadvisor. We booked him for a day walking trip through Jerusalem. He was a great introduction to the city. We then got much more out of the city when we wandered around by ourselves. We also booked Sasha for a day trip to Masada, Ein Gedi, and the Dead Sea. Overall, I would describe Sasha as:
1. Responsive -- Sasha answered so many questions before we left and we so responsive that we booked the second day with him.
2. Informative - We talked history, Israeli politics, cooking, religion. You name it.
3. Easy to be with for two days.