I did, went from old black and gold mono m4s to newer style evo m4s. Both were/are on 200mm front/180mm rear floating rotors and both had/have braided hoses.
I used to find I could cook the old mono m4s quite easily, where the new ones I can’t. There is much easier adjustment with the evos, which is good for me as I like my levers with next to no movement and at a long reach.
Braking performance wise there is not a huge amount of difference, the evos need no real effort for braking, and as such I’ve found on long alpine descents I get less arm pump compared to the monos. Servicing wise, it is the same story with both, piece of cake to work on and spares can be had anywhere.
Besides that, I prefer the look and lever feel of the evos, and the silver calipers don’t look as battle scared so easily.
Go on, treat yourself, you know you want to!