It's easy to find people complaining about vignetting and poor fits, so what should someone know before buying the adapter and lens? Which C Mount lenses are a good buy? What are the likely focal lengths available? What are the apertures? What's got the best bokeh? What are the manufacturers worth checking into?
Part of the fun of the µ43 format is availability of lots of older lenses, but there's a serious dearth of centralized information on options to explore.