I have purchased both Panasonic and Olympus, so have no bias that's for sure. I have had issues with both my E-M5 and my EP-5, but only a vague symptom with my GX7 (sometimes not switching on), and it's far too early to say anything about my recently acquired GM5. Nothing scientific, but scanning the threads in the respective sub-forums, there appears to be a reduced number of build issues reported with the Panasonic brand compared to Olympus. Viz: lower number rear dials reported as not working (I could only see one and that appeared to be misuse) or any dials not working in fact, not as many eye cups falling off (if any), no rear screen bezels cracking, and in fact very few people seem to be moaning much about Panasonic. It would be unwise to conclude from this, but Panasonic seem to have something going on, whether by design, build or both. Or it could be that there are more Olympus users out there, so more cameras to go wrong.