The biggest benefit is the comfort level of a split keyboard with tent/tilt. I've used some Kinesis keyboards and a Mistel Barocco and those are fine, just get a split keyboard with tent/tilt.
The ortholinear layout took some getting used to, but now I very much prefer it. However, everything else about it I liked right away: split, ergonomic, mechanical, easily programmable, controls the mouse, dual-function keys, etc. And I've gotten used to the ortholinear and very much prefer it.
The 2 complaints I have are the thumb clusters are not ideal for me (it's difficult to reach the 4 small keys), and the tilt kit doesn't tent/tilt enough for me, and it's difficult to keep it in the right configuration.
I use an IBM Model M at home on my main PC (my first model m), which was a gift from the energy, animation, and electronics office at my former workplace. It was sitting for years on a desk next to it's replacement PC (and nasty rubberdome kb) until I chanced across it.
In the computer lab, I have a Unicomp Model M Classic.
At work I have a Unicomp ultra classic.
At my moonlighting workplace, I have the knarly layout Unicomp PC 122 keyboard.
And finally for travel, I have an IBM model M I snagged for 20 bucks in Craigslist.
Do I have enough keyboards? No. I want to get one of the unicomp trackball keyboards so I will have a buckling spring keyboard with a built in trackball mouse.
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Someone put it out in a "Free Stuff" box and I grabbed it. It's in pristine condition.
And that was a week after someone else put out some ancient computer science and programming books. Including a copy of Knuth vol. 1 in much better shape than my well-worn copy.
In Berkeley I have seen a lot of valuable stuff in the streets after each semester.
When, or maybe if, this Model M fails, I'll pick up a run of the mill $30 keyboard.
In the beginning I thought it's decent. Now a new computer was set-up at the next desk with a brand-new keyboard of that kind. When I had to type something in on that new Dell keyboard of the same kind, the tactile feedback was much clearer. I am assuming it feels better since it is new and the rubber domes (needs verification) are not that used.
At my desk I am now getting annoyed of the worn out feeling. It's interesting how perception changes when you have a direct comparison.
I'm using an old Microsoft keyboard. The new ones are not good, particularly the Natural Ergonomic Keyboard 4000, because the keys aren't in straight rows. Mine has that split in the middle, but is otherwise a perfectly standard qwerty layout. I get a bit more comfort without having to relearn how to type and thus become incompatible with normal keyboards.
The older the Microsoft keyboard, the better it is. The original was very much a premium keyboard, with big aluminum plates inside it for rigidity. The slightly later ones with multimedia key are OK, at least if you get the traditional arrow keys. (what I have) On the more recent keyboards, the keys are all different sizes and misaligned.