Solar is absolutely reliable. In the end, though, the bottom line reliability comes down to the overall system design, meaning: (1) identify your power needs based on location (daily sun hours, weather/climate) and power consumption profile; (2) buy tried and tested products; (3) solar panels are cheaper than batteries, hence: run high power draw consumers (well pump, washer/drier, dish washer, water heater etc.) during day hours; (4) buy long-lasting and low-maintenance batteries (LiFePo4 as opposed to LI-ION, AGM, FLA); (5) install an easy monitoring system; (6) build in failsafes (fuses and breakers between panels and the solar charge controller, for example; (7) don’t skimp on wiring and mounting; (8) have spares/backups for the most important components; and of course, do proper system sizing.
Also, what @Uncle_Gabby said, mostly.