I do not recommend (Presenting problems - I just have used 3 times- Less than 2 hours of use in 1,5 years)
Not Reliable. Noise originating from the flash's zoom mechanism. I get both the Auto Check and Test/Charge lamps flashing and I can't get any flash firing. You will find several complaints in a simple search over internet.
Note from Olympus:
Please contact our support at 1-888-553-4448 (M-F 9am to 9pm).
The Match Made In Heaven
The OM-E-M5 and this flash make for a truly professional capable combo. They work in perfect harmony together providing flawless flash exposures. This model flash has the best flash recovery speeds between shots and is bright enough for every occasion and venue. It's diminutive size belies it's capabilities. Complete control via the controls on the back along with it's powerful output and you have the BEST combo for your OMD body. It will in NO way hold you back. Because it also provides the handy bright LED video light within the body you'll get superior video results as well. I shot a video with the subjects over 15 feet away and it looks amazingly natural, not as if they had a light glaring on them. Nice compatibility with common AA batteries allows for your NiMh battery use increasing not only usage life but also lessens the times between flashes. 180 degree rotation on the flash head just adds to it's versatility. This is a MUST have for a OMD owner.