It's interesting that you mention viewport performance. Two of the major drawbacks of Blender are mesh edit mode performance and sub-d modifier performance.
In fact, v2.8 introduced regressions in these cases! And earlier versions were pretty bad at dealing with heavy meshes.
With v2.93 the devs finally realized that mesh editing had become too much of a bottleneck. I regularly test various DCCs how they cope with heavy meshes. Blender did not cope well at all. Only LightWave Modeler was worse. Cinema4D (before the core updates) did a little better than Blender 2.8, but only by a slim margin.
V2.93 improved mesh editing to a similar level of performance of C4D 23/24. Perhaps a tad slower for medium-heavy meshes. That said, C4D chokes completely on heavier meshes of 2 million polys when I try to select all of them and transform. Compared, B 2.93 keeps chugging along. Blender is better at dealing with heavier data sets, as far as my tests indicate.
But. BUT! The Blender devs have been hard at work this Summer doing a mesh performance improvement code sprint. v3 alpha is by far more performant now, and leaves Cinema4D 24 far behind. My tests indicate that v3 is as about as fast as Houdini in regards to pure raw mesh editing, much faster than Maya, and much MUCH faster than C4D. At this point only LightWave Modeler is slower than Cinema4d.
3ds Max is still king of the hill, though: it munches through heavy meshes without breaking a sweat. It's in its own league, and nothing comes close.
The B devs have also been hard at work improving the sub-d performance, btw.
As far as sculpting performance goes: Blender already outpaces C4D by a wide margin in my tests.
And as you @DasFrodoalready mentioned: B deals easily with far more objects in a scene than C4D. In my tests that is also quite obvious. C4D is relatively quickly brought to its knees with hundreds of objects, while B happily devours thousands.
I have to say that I was surprised to discover that 23/24 performed quite poorly in regards to heavy mesh editing, since the core update ought to have delivered more performance? I don't know. Perhaps the upcoming R25 will be the real performance booster update.
All in all, Maxon MUST improve C4D's overall performance to keep up with the competition. In particular when the upcoming free option leaves C4D in the proverbial digital dust.