I regularly get spilling beachballs on my 2019 27" i9 iMac when working in Office and Adobe Acrobat Pro. They're merely small annoyances—lasting 1–3 secs—but it would be nice if they could be reduced. [At least they're briefer than on my 2014 15" Macbook Pro.]Honestly, I've found that the Intel Macs don't really feel much slower in normal day-to-day use. On Apple Silicon, Mac OS is trying to use the efficiency cores when it can. These cores are nowhere near as fast as the P-cores, so you aren't necessarily always getting the full performance of the processor when Mac OS doesn't think you need it.
Work sent me a 2017 Macbook Pro with a dual core 7th gen i7, and it geekbenchs about 980 SC and 2400 multicore. It honestly feels just as snappy on most day-to-day tasks as my M1 does (1700 SC, 7600 multicore). It's to the point where I sometimes forget which machine I'm on, and that's despite a pretty massive difference on the benchmarks.
Apple Silicon of course clearly wins on power efficiency, and it also obviously wins massively on raw performance for pretty much anything that is even remotely demanding (as soon as I start running XCode builds for iOS apps, I feel it immediately). But I wouldn't say that everyone is in for an earth shattering difference on the speed of their systems either, some of the more recent Intel ones are still quite snappy and are perfectly fine for a lot of people. For real-world "everyday tasks," the difference sometimes hardly even feels noticeable.
Do you get these when you're working and, if so, do you see a difference between your 2017 MBP and your M1?