Apart from noisier images at higher ISO it's hard to find much fault with images produced with decent M43 gear. It's not 'fanboys' claiming this or that, it's more the case of constant naysayers putting the system down and the users who know better continuously having to defend it. It gets pathetic tbh, every time M43 is mentioned the equivalence police are out in force - as if it was some weird threat to their precious FF gear [it's mostly FF gear heads do it] These naysayers don't get the advantages, for wildlife, macro and landscape, that deeper DOF at lower apertures in a bonus. I found in particular for macro I could keep more in sharp focus easier at much lower apertures, often found F8 sufficient even for 1:1 of tiny bugs. You're not doing this with APSC or FF, you know you'll be stopped down to F16 or even more or barely anything will be sharp
A bit of noise in your images isn't the end of the world, there's not much else to moan about with the system. Cameras like the em1mkii and G9 have much better DR than some like to make out too. With my old G80, using the older 16mp tech sensor, I was able to push files pretty hard in post - I was pleasantly surprised when I first started processing M43 images. Sure, I did switch back to Fuji, but I was shooting Fuji before M43 and always said w=once they had IBIS in their bodies I'd give them another go - had to wait for the H1 to drop a lot in price first .... which has happened. But I'd definitely use M43 alongside if funds allowed.