I drove my car (unfortunately not a 1M, but as close as I could make it without going crazy) and my friend's lightly modded m2cs which I drove with the stock tune and a fast tune. I also drove it back to back on the street with my own car and previously driven a stock n55 m2 on a autox course a few years ago (both m2s were dual clutch).
The m2cs steering feel and suspension felt improved from the older first m2, but still lacks the steering feel I get with my 135i. The m2/m2cs also felt a lot more stable and has much more traction than my car, that being said the extra power of the m2cs still makes it tail happy. The stability is most notable over bumps, but I think that might be due to me putting the subframe inserts in instead of the full M rear sub frame bushings replacements. The m2 also doesn't tramline nearly as much as my car either.
The extra power from mods + the dual clutch makes it feel crazy fast compared to my 135i with just an exhaust, tune, intercooler, and inlets/outlets. The stock power feels close to what I'm making now in the 135i with my mods. When I drove old M2 it kinda felt slow to me, but it felt really balanced.
I still don't really like BMWs infotainment and electronics stuff, but there's really no avoiding it anymore. The ergonomics for everything is good like any other BMW.
I'm not willing to get rid of my 135i yet, but once it starts racking up more miles and becoming less reliable I'm likely going to probably start looking at the m2 and m2cs. I can't think of many new cars today that have that level of power, handling, comfort, and have room to carry nearly everything you could need it to for the price.
I def would not get rid of a 1M for one, but maybe in addition to it
