I got an M4 as a new work machine and it is absolutely bonkers how much faster and quieter it is. And the battery lasts forever, even when running my dev setup. I can actually go and work at a coffee shop for a couple hours without taking the charger now.
Same here. My slightly older M2 MacBook Air seems to be allergic to electricity. I wouldn't be afraid of leaving the house without a charger before a full day's work, as long as I'm not planning to run compute-heavy stuff the entire time.
I used to have one of these and recently got an M1 Max machine - the performance boost is seriously incredible.
The throttling on those late-game intel macs is hardcore - at one point I downloaded Hot[1], which is a menu bar app that shows you when you're being throttled. It was literally all the time that the system was slowing itself down due to heat. I eventually just uninstalled it because it was a constant source of frustration to know I was only ever getting 50% performance out of my expensive dev laptop.
[1]: https://github.com/macmade/Hot