I owned the 14-140mm f/3.5-5.6 lens for over 6 months using with EM5. The result is really very good. No problems encountered.Anyone using this lens on an Olymp E-M5
Note that the OP mentioned the 14-140/3.5-5.6, which has only been out for 8 months, so your experience is probably with the older 14-140/4.0-5.8.I did for maybe a year - no issues. It is not going to rival some of the sharpest lenses, but it makes very good pictures (like those above) and is a very useful single-lens solution as long as you don't need to shoot in bad light. I only sold mine because with the 12-35 and 35-100 it really seemed mostly redundant, not because of any dissatisfaction with the lens or its performance (on either my EM-5 or the GX-1 and G5).