Reviewers mostly praise Spark for taming crowded inboxes: smart sorting, spam control, snooze and pin workflows, strong multi-account sync across devices, and a clean interface that helps people reach inbox zero. It is especially valued on iOS, Android, and for team use. But the redesign sharply divides users. A vocal group says newer versions feel slower, more restrictive, and less feature-complete than Spark 2, with crashes and weak Windows parity. Pricing also draws complaints, especially when basic tools or extra accounts sit behind a subscription.