Reviewers mostly praise SigmaOS for a fresh workflow built around workspaces, split view, and heavy keyboard use, saying it helps them stay organized, focused, and more productive once the model clicks. But the same shortcut-driven design is also its most common complaint: many find it hard to learn, conflict-prone, or disruptive. A second recurring issue is reliability, with reports of lag, glitches, weak extension support, broken institutional SSO flows, and uneven customer support. Mac-only availability also limits adoption.