Okay, still far from ideal weather, but here goes. I have compared the EF-M 18-150 with the EF-M 18-55, both wide open at f/3.5 on as close as I could get identical shots. The first image is the whole scene from the 18-150 @ 18mm f/3.5. The post following shows crops from the new 18-150 then the old 18-55 for direct comparison. I chose the far left side for 100% as it showed the difference the best with what I had available. All shots processed in DPP with appropriate Canon profiles - had forgotten what a dire piece of software DPP is!
I did the same test with the new lens at 150mm wide open and compared it to the EF-S 55-250 set to 150mm wide open. The only discernible difference was that the EF-S is a faster lens. As far as IQ was concerned I could tell no obvious difference anywhere across the image between them. I don’t see any point in posting those comparisons for that reason.