The difference is that one keyboard is made for humans who touch type, and the other keyboard is made for people who like to lift up their hand and move it every time they want to hit return... or left shift.
The ones with the shorter left shift and narrower/taller return key are just bad designs. They make keys you use frequently less accessible, and the tradeoff is that keys you rarely use are now in reach.
I'm not in the US, so I'm kinda alone in this, and forgot to tell my work I wanted an international one, so I got an M1 pro from work with the international lay-out.
I've been using US layout since I was ~8. And all my other systems have the US layout. I am having such a hard time to get used to it.
I keep hitting ± when I mean ~ (why would I even need a ±/§ key on my keyboard?). I keep hitting \ when I want to hit Return. I keep hitting ~ when I want to hit shift.
I had this as well with a previous company work laptop, so I had to use a wireless external keyboard always. Using the built-in keyboard was so frustrating that it made me angry enough to almost destroy the laptop a few times.
It should be noted that on older Macbooks, the aluminum case has actual cutouts for keys. So it's not possible to change the layout of keyboard without also changing the case. I discovered this when I had my personal laptop repaired, and it came back with the wrong keyboard! The shop just instinctively ordered keyboard+case of their usual layout, so I had to have the whole thing redone again (at no extra charge, just a loss of time).
Well there must be at least 3 of us, because I'm another one. I've used the US layout ever since you could save something like 28 KBytes from not loading the UK layout, and I used this with UK keyboards for years. (Very useful having a backslash key for every hand.) Then at some point I acquired an actual US keyboard, and I was an immediate convert. I just really liked the fat Return key.
When I bought my first MBP, I wasn't completely wedded to the idea of getting a Mac necessarily - but when I noticed you could order one with a US keyboard, it tipped the balance in favour.
(For any serious work, I use a USB keyboard and mouse, so in a sense it doesn't really matter. But I use the built-in keyboard often enough that I'd be annoyed being stuck with that tiny Return key...)
(This reminded me: if you go to get a battery replacement, make sure the staff member notes that it's got a US keyboard. I took mine to a UK Apple store for a battery replacement a couple of years ago, and when I went to pick it up a few days later, it had had its keyboard replaced with a UK one! The staff member was very apologetic - perhaps they correctly read my expression of speechless shock after opening it - and it got fixed, but it took a couple more days. So in the end I was without my laptop for over a week.)
That's interesting, the one I'm typing on right now seems to be a hybrid, longer left shift (which is indeed better) but tall enter (which I like because I like to just smack it from time to time).
The difference is that one keyboard is made for humans who touch type, and the other keyboard is made for people who like to lift up their hand and move it every time they want to hit return... or left shift.
The ones with the shorter left shift and narrower/taller return key are just bad designs. They make keys you use frequently less accessible, and the tradeoff is that keys you rarely use are now in reach.