Many swear only by the Panasonic Leica 42.5 1.2 Nocticron or the Olympus 45 1.2.
These lenses are 3 times more expensive and honestly not so way above what i use to call, The Great small Micro 4/3 portrait beast : Panasonic 42.5 1.7.
PROS
For a weight of only 130 grams, it delivers a remarkable sharpness wide open in the center and almost identical at the edges !
Chromatic abberations are well controlled and the extremely low level of fringing should be difficult to spot.
The A.F is fast and reliable.

The level of details is breathtaking. I’ve used the lens for street, close up photography and even concerts ! I had to chance to have the accreditation for a Supertram’s Roger Hodgson concert and i mostly used only the Panasonic 42.5 1.7. (As i was in the pit, I started the concert with the Olympus 12-40 f2.8 Pro)

As this focal length is usually used for portrait photography, i was never disappointed by the results it produced.

As the focus distance is only 30 cm, it also allows very close shots.

It has an internal stabilization (The Panasonic cameras owners will benefit from a double stabilization)
CONS
Not weather sealed, nor stamped Leica.
No MF/AF button
and then that’s pretty all !
CONCLUSION : Fantastic!
No need upgrading to the Olympus 45mm 1.2 or the Panasonic Leica Nocticron, except if you absolutly need the weather sealing and/or the best image quality !
Wish to Buy the PANASONIC 42.5 1.7 ? ( Amazon Affiliate Link that would help me to continue the adventure…It won’t cost you anything more and i’ll receive a little contribution)