Just went to the Russian booth at the Fair of Nations on Reforma over the past weekend and Kolobok sponsored the booth ... the food was as good as ever.
A few years back I went with a friend from the UVM which is close to the Santa María location and everything was delicious with good service. The soups are particularly good.
Recommended as an off-the-beaten-path destination for anyone visiting Central Mexico City.
I have not tried the Universidad location but they tell me it is different but just as nice ... I cannot wait to get there one day!!