What was the bad experience?
I value AF a lot so most of the bad exp comes from AF related issues.
1. No PDAF in video, CDAF is possible but area is so small in the center, that makes it vlog only.
2. Poor compatibility. Whether is Metabones, Sigma MC-11 or Viltrox. Early EF, 3rd party EF, niche lenses are not working every so often. Even Sigma's EF are limited to the late EF-era lenses.
3. Continue from point 2. Adapting lens will give unreliable PDAF in AF-S & AF-C. Even with subject/face recognition on, it will jump to somewhere and lost AF ability at some point. Even casual shooting will cause you miss good moments.
4. As I mentioned before. The early E-mount APS-C lenses from all parties will not work well with latest Sony bodies. The pancake E 16mm f2.8, Sigma 19mm F2.8 DN | Art e.t.c.... will end up only center AF zone available, or random pulsing. Those lenses are not more than 15years and it's already software limited by Sony. I couldn't imagine what will Sony cripple them 5years later.
With Canon, when your camera fails something there's some sort of error code appear for reference. For Sony, you don't...just getting blank dark screen.
One thing I have to praise Sony is they allow custom buttons to set APS-C mode with one button press only. My R6 still need to press and roll the wheel once to 1.6 crop mode.
I'm keeping my current Sony gear is because there's no complete replacement of 20G, 28-200, 200-600G in RF. Once Canon allows SigTam entry or provide equivalent lenses. I'll sell out my Sony gear. Losing the insignificant advantage dynamic range and Slog3 is acceptable.
Everyone bashes Canon for no 3rd party. Yet Canon retains strong compatibility for old EF lenses in stills are not appreciated enough. Using RF body with cheap EF lenses is super cost-effective. A lot of times are not about getting super sharp and flat colors for easier post-processing. SOOC when possible and getting those non-fuji film colors are nice.