I had full 24 month (by law) + 6 additional month after registration at Olympus on my 17/1.8. Probably coutry specific.I agree that it is better to buy an Oly refurbished lens or camera than a used one, and probably worth a little more money. However, I think you only get a 90 day Oly guarantee , not a "full" one. I bought my E-M10 MarkII a few years ago from Oly as a refurb and seem to remember being concerned aobut the shorter warranty.
I don't mind it either, at all. The 17mm f2.8 is almost like a Lomo lens - it's not sharp but the colors are good and the overall macrocontrast is really nice. Images it makes are what I would call filmic, i.e. they feel like they have some texture, especially in high ISO.the PL15 might be worth considering if you want wider than the 17's but think 12 isn't general purpose enough. its also a great lens optically, probably my favourite.
i actually dont mind the 17/2.8 . its small and has its own look in rendering. sharpness isnt always everything.