I agree. I also replaced my 42.5/1.7 with the Siggy. Though the 42.5 is certainly more compact, and it was a fine lens, the Siggy 56 just feels a step up, and of course the wider aperture helps.I bought this lens a while ago to replace my 42.5mm 1.7. I wanted a little longer prime for outdoor shooting and head shoulder portraits between the 75mm and the 42.5 (to make it a little more versatile yet perfectly suitable for head&head/shoulder work) and this one fits right in. I love the IQ I get out of this lens. It's razor sharp @1.4. Even when taking full body shots. I'm also very happy with the focus... It works more reliable compared to my copy of the 42.5 which missed occasionally especially from a longer distance.
The only time I feel as if there's any noticeable focussing delay is when trying to close focus; however, the manual focus ring is excellent to use, so it's easy to focus using a half press of the shutter button then adjusting with the focus ring. This is on GX9 and G85.How is the focusing for this lens on the G9 compared to similar native lenses? Thanks!