You can take a mediocre 200W design, market it as a 300W unit and it should do great for years as long as its output never exceeds ~200W.I have an 7yr old Okia 350 that is working day in day out. Not missing a beat. Of course there is hardly a load on the PSU!!
Step-Thermodynamics, it's at least 11yrs old and still going. More than I can say about Step's business.