Usually it is seller's agent to choose the escrow for seller. Buyer can choose too if the escrow account is not open yet and if seller is ok with that. which escrow agent choose really depend on the relationship between escrow officer and the agent. That is why listing or selling agent always try to use their escrow officer. If we use the same escrow officer all the time and happy with their service, we will do the same. Different escrow company might charge little bit different but in bay area CA, it is no significant difference for the cost.