- For native M1 apps like Pages, Sublime, or Highland there's no lag at all. For example, with Highland 2 from double-clicking a file to editing it is less than a second and there's no lag during use even with a 49,000 word book manuscript open.
- For x86 apps like the not-quite-latest Office there's a couple of seconds at first launch (for that session) whilst Rosetta does its x86 translation work, but after that it launches without lag for the remainder of that session and it stays snappy in use (snappy for Word that is).
- Native VS Code goes from launch to editing in under two seconds and never lags, even with something like side-by-side Markdown preview going.
- If you're using Vellum for publishing it's about 1.5 seconds from double-clicking a file to editing it.
Battery life is, indeed, impressive.
Last night I spent around 5 hours doing C# dev in VS Mac, with multiple projects being built every few minutes, cross-platform binaries for Intel Mac, Windows, and Linux being produced every half hour or so, plus Highland 2, Word 2016, and Vellum. With all that it used 28% battery across that 5 hours (and never got warm). On full brightness too (for my sins).
I know the question isn't about dev, but writing uses less resources and gives even better battery life so 18 hours (for example) is definitely possible.
The only issue I have is the keyboard. Far better than the 'broken' ones of a few years ago but I really wish they'd go for thicker machines and increase the travel. I've just got rid of my last ThinkPad and it's the one thing I miss.
Oh, and there is no longer a hotkey to control the backlight brightness; it's automatic. Which genuinely works perfectly except that it doesn't come on for your very first sign in at boot-up, so entering your password then can be tricky without ambient light (though after that you can use the fingerprint reader). It's a really strange UX flaw. Not related to your question, I know, but you don't say whether you're already on a Mac or switching so I wanted to be honest about this as it is really annoying but rarely mentioned.
It's shocking how an OS update can still take upwards of an hour on what is otherwise such a fast system.
My 8-core 64GB Windows machine fares no better.
Switching between OLVWM desktops on my 200MHz Pentium Pro twenty years ago was instantaneous.
(I'm on an M1 Air and I think the performance is great)
I'm asking because I've been thinking of getting a MacBook Air in the future with the intent to use it for writing.