I purchased this lens as soon as it was available and after using it for the past 5 days, my only regret is that I did not have this lens years ago. I have been a Professional Photography for over 25 years shooting primarily images with people as the subject, so portrait lens are important to me.
I have used some great professional portrait lens but this lens exceeds them all. It is super light weight yet built like a tank. The image quality is THE BEST I have seen for any lens that I have used wide open, except for maybe the M.Zuiko 12-100mm, but that is f4.0. One of the things that I noticed when I was walking around taking portraits of people on my photo walk, was the incredible speed of the Auto focus system. On my OMD EM1 Mark 2 or my Pen F, the image was just in focus, no hunting and ready to shoot before I was. I never waited for the focus, I just waited for the right expression or moment. I used the lens mostly at f1.2 and after looking at my images there really is no need to stop down.
I own the M.Zuiko 75mm f1.8 also and I took both of these lens out to compare them. My hope was that the image quality of the 45mm would be at least close to the 75mm, which in itself was my favorite portrait lens. When I compared the images, it seems that at f1.4 on the 45mm, it matches the IQ of the 75mm, which is amazing if you know who sharp the 75mm lens is.
This is my new "Never take off my camera lens", it is that good.