Alex's tour is a good dichotomy between the food and the history of Central Asia. Very fascinating to learn about this part of the world as we in the US receive only scant information about this region in the normal course of studies. We visited several markets where Central Asian food and products were sold and ended with an awesome lunch. I very much recommend his tour if you're from a part of the world where you can't get Uzbek food as this is a good place to taste it! I have a suggestion which would be to offer a tour where one could learn how to make Uzbek/Central Asian food (since it's so hard to come by outside of the region).
Olga was a great tour guide. She introduced me to some of the creative places and movements in Saint Petersburg and described the causes/initiatives for which they were founded. Her English was superb. I would recommend taking her tour if you want to see a side of St. Petersburg you might not expect and get to know some exciting developments which are in store!