"short summary for pre-Mariko units:
1.0.0: has a nice non-coldboot solution, and is the most likely to get a Holy Grail CFW-launching exploit in the future
<3.0.1: has enough power to avoid a hardmod immediately, even if you'll probably want to just do the hardmod 'cuz the hardmod's so easy
<=4.1.0: will eventually see a hardmod-less solution, but will need that 'minor hardmod' at launch
>4.1.0: that 'minor hardmod' is required; though we may find a solution to avoid this in the future"
"I do have a "hardmod"-assisted variant, where the hardmod is approximately equivalent to shorting a couple of pins with tweezers. No soldering or dangerousness required, and there's a very minor thing you can do (think the equivalent of snipping a pin) to make the assistance permanent.
There's also a neat twist on things that allows you to do the above with no permanent modifications to your Switch."
~Kate Temkin