Yours is about twice as old as my Cateye Strava Cadence. Aside from having to change the battery every other year (no reset on the odometer function), it measures speed, cadence, and distance in heat, rain, and cold, through tunnels, under heavy tree canopy and near bluffs that block out large parts of the sky, with no problems.

Just a suggestion: people complaining about "cycling computer reliability" might let the rest of the forum know what they want to measure, and why. Is there a reason you need a GPS?