For the EPL10 (m43), there is the options of the oly 60mm f/2.8, Oly 8mm f/1.8 and pana 8mm f/3.5. They are quite bright.
I bought the EPL10 mainly because it is small and compact but has more versatility and potential for growth (versus Canon G series/ Pana LX10). I've chosen the Oly 60mm for macro/fish portraits and 14-42mm + WWL-1B for my wide angle (more versatile than the 8mm because it allows for zoom thru IMO). I use them with a pair of Z330s.
I am very happy with the 60mm for macro/fish portraits, AF is very snappy. Custom white balance is very good as well. The 14-42 mm + WWL-1B combo I have not been able to try yet because of travel restrictions.
I also agree with Chris that TTL is a hit or a miss and depends on the camera. Shooting manual yields way better results most of the time. You can also stop up and down in camera so you don't have change strobe power settings.