Accessory talkThis section of the FTU forum is for discussions concerning all aspects of Four Thirds system accessories, including flash, extension tubes, teleconverters, etc.
Both Metz and Nissin are very good; Metz guns can be a bit simplistic but they are relatively affordable. I would also recommend looking out for a second hand Olympus FL flash on eBay, for example - FL-36 or FL-50. The R-designation of some FL models means wireless remote control compatible. Panasonic doesn't support this mode, but these flash units also have a simple slave sensor for off-camera use built in so that could be useful one day, or if you eventually get an Olympus body (though not an E-PL1 as this doesn't support wireless control). I don't have any experience of the other brands.
I'm using a YONGNUO 560 II with my Panasonic G5.
It does not have TTL but I like it very much.
It is not expensive and is equivalent in features and quality to much expensive models.