I mean, I have a 2TB SSD on my 2017 MacBook Pro w/TouchBar 15-inch and honestly would have trouble with anything less than 1TB minimum... I don’t know how Apple gets away with 128/256/512GB storage... do people not use their Mac computers the way they used to for performance based projects? Because I do and I honestly need the space, iCloud is great and all, but I need local storage, too. Lots of it!
So yeah, if your only choice is 128 or 256GB, I would have to “recommend” 256 in this case... 128GB is just not enough and in my experience you’ll constantly be deleting stuff and running out of space. My iPhone is 256GB and even it is pretty much full, what with 30,000 photos, many videos and iMovie projects I tinker with on the go, etc.
More storage FTW!
Cheers
PS: I hope you get my lighthearted humour here. While more storage is critical for me, if it isn’t important to you that’s perfectly ok. But for what I use my MacBook Pro for, I had to max out all specs.