Let both cities submit proposals with a program and price list, then allow some time for price optimization, and then we can make an informed decision!
Also, when making the decision, it's important to consider whether those who voted for one city will be able to travel to the other.
The main criterion, as I understand it, is to maximize the number of participants?
And I'm sure that Yekaterinburg will be significantly cheaper in any scenario than Sochi (which means we have a +9 advantage :p).