Switched to an MVNO SIM-only plan two years ago, never looked back, but let me give the honest nuance. The MVNOs (the budget brands) actually piggyback on the big three's networks, so in most of Singapore your coverage and speed are essentially the same as the parent telco, because it IS the same towers. For normal use, scrolling, streaming, maps, video calls around the island, I genuinely cannot tell the difference and I pay a fraction of my old bill with way more data. The catch: during congestion at big events (NDP, countdown, packed stadium), MVNO traffic can be deprioritised behind the parent telco's own customers, so speeds may dip when it is super crowded. Also customer service is app-based and bare-bones, no fancy retail store hand-holding, fine if you are comfortable self-service. And you usually bring your own phone, no bundled handset subsidy. My advice: if you don't need a subsidised phone and you are okay with app-based support, an MVNO SIM-only plan is a no-brainer for most people, huge savings. Just pick one riding on a network with good coverage where you live and work. You can always port back, number portability is easy here.