I'm sure I've said this before but the Olympus 75 f1.8 must be one of the sharpest lenses I've ever used. As a matter of fact I find the m43 prime lens offering presently to be of top quality; from both Olympus and Panasonic. I can name a few that really are excellent; Olympus 12 f2, 25 f1.8, 45 f1.8, 60 f2.8 macro and the 75 f1.8. From Panasonic the 15 f1.7, 20 f1.7, 25 f1.4, 42.5 f1.2. For these lenses I can vouch personally because I own them. For the others I can't say how they perform but I have no doubt they're just as good. In my opinion these modern lenses from these manfacturers are just as good as the best quality from Nikon and Canon.

The only manufacturer who is behind the times is Sony who surely must do something to improve it's lens line-up. They are slowly bringing more lenses to the market but they are larger and a lot more expensive. Granted they are FF lenses, but without the lenses you don't have a system.