The 3 banks are very competitive and generally offer the same services at same cost.
Unless you qualify for private banking and have a particular banker in mind, there's very little benefit that can be derived from jumping around local banks. Foreign banks usually give slightly higher interest, but again unless your sums are huge enough to make a difference, they aren't worth the inconvenience.
DBS is the best in terms of platform. The only banking app that combines all my savings, investments and allow me to trade directly. Might make a difference if you are a DBS Treasures customer too. Minimum $350k to start a relationship.