I think overmount is better than undermount. Firstly, it will be supported by the table top. Secondly, we can ensure the seal between the sink n table top is in good condition. Thirdly, we might not need a concrete support to hold the sink as it was supported by the table top. Fourth, changing of sink is easier. We must understand what is the concrete structure supporting... The sink or the table top... But for long lasting kitchen cabinet, it is still recommended to have concrete supports near the sink and hob area.