Krankenkassen are private companies but their basic-insurance arm is heavily regulated: they must accept every applicant for basic cover, cannot discriminate on health and must offer the same legally defined catalogue of services. Differences between insurers exist mainly on premium price, customer service and the network of doctors in alternative models.
Beyond basic insurance, the same insurer typically offers complementary insurances (VVG/LCA): private/semi-private hospital wards, dental, alternative medicine and travel. These are commercial products and may refuse applicants based on health questions, so taking them out while young and healthy is recommended.
Switching basic insurer is possible by 30 November each year, taking effect 1 January. The annual premium-comparison tool published by the Federal Office of Public Health (priminfo.admin.ch) is the official source; private comparators (comparis, bonus.ch) add extra filters.
A family of four in Zug switching from a CHF 510 average-adult premium to a Krankenkasse offering CHF 410 with the family-doctor model saves CHF 100 × 2 adults × 12 months = CHF 2,400 per year without losing any basic coverage.