There is a computer keyboard, called the Happy Hacking keyboard (HHKB). It is a keyboard often loved by “hackers”, and is one of the most idiotic keyboard. Let me count the ways.
It lacks 12 function keys. TWELVE of them! One, two, three, …, four, five, six, and more. Continue counting: seven, and eight and nine. Then, we add another digit to hit 10 in a decimal system. Then, eleven as in Seven-Eleven, and twelve, as in: twelve days of xmas. Twelve programable keys down the drain! What to do if you need them? You have to press 2 keys: 【Fn+‹key›】. What happened to the concept of efficiency?
Bygone are the extremely convenient dedicated page navigation keys: ↖ Home, ↘ End, ⇞ Page △, ⇟ Page ▽.
Of course, PrtScn, ScrLk, Pause keys, and the entire set of 17 keys on number-keypad are gone too. Sure, you can do without them, but for programers, that's another 17 programable function keys gone.
On the “professional model”, there's not even arrow keys.
Happy Hacking Keyboard is supposed to be used by hackers, right?
Ok, now you lost 33 keys to automate your work. To make up the lost keys, the Ctrl+Alt+Meta must be going strong on the HHKB. But on HHKB, it has fewer modifier keys than cheap generic PC keyboard! WTF⁈
There's Alt and Ctrl, ok, and there's ◇ Meta and Fn. Where's my ❖ Super and Hyper keys? On a standard $15 PC keyboard, i have 1 or 2 more modifier keys than the $80 Happy Hacking. Let's count.
$80 Happy Hacking (or ≈$260 Pro model), you have:
1 Control, 2 Alt, 2 ◇ Meta, 2 Fn. (the Fn can't count here because usualy it is hard-wired in the keyboard circuitry thus the OS doesn't see it.) That's a total of 7 modifiers. If not counting Fn, then it's 5.
On $15 nameless USB keyboard, you have:
2 Control, 2 Alt, 2 ❖ Win key, 1 ▤ Menu key, 1 Caps Lock. That's a total of 8 modifiers, all of them can be individually remapped by software on {Windows, Linux, Mac}.
If you look at the distance from F to the left ◇ Meta versus J to the right ◇ Meta, you see that they are not symmetric. The right side modifer requires you to curl in thumb deeper.
Many cheap PC keyboards have the modifier keys symmetrically positioned. (⁖ “Microsoft Wireless Keyboard 2000” ($21), Microsoft Comfort Curve ($17), “Microsoft Natural Elite” (≈$30) amazon, and lots others from other brands.)
I presume those who like HHKB are unix users and the reason they like it is due to some key's layout.
Each of these key positions are actually inferior to optimal. For example, if you are vi user, the optimal position for Esc is where the PC keyboard's Caps Lock is at, or, one of the big Alt right under thumb (a design point popularized by Maltron ＆ Kinesis.).
If you are a emacs user, the optimal position for Control is the 2 big Alt key on Microsoft ergonomic keyboards right under your thumbs, 2 of them, symmetrically placed, pressed by a strong finger thumb. Or, alternatively, as Caps Lock on left side AND the Enter ↵ on right side. (a design point advanced by Truly Ergonomic keyboard.)
See also the original keyboard vi is designed on at How Emacs ＆ vi keys came to be.
Note: the “Professional” model of the HHKB amazon has mechanical key switch. It uses capacitive switch (Topre), supposedly better than Cherry MX switch. See: Guide to Computer Keyboard Key Switch Mechanisms.
The “model lite 2” model's key mechanism is rubber dome. amazon
For why the function keys are important, see: Increase Productivity Using Function Keys.
If you really like Happy Hacking's compact size and mechanical key switch, i'd recommend Filco Majestouch Tenkeyless or Cooler Master. There, you have physical F keys, plus nav keys. Highest quality keyboard, yet about $150 cheaper than HHKB.
Even better is Truly Ergonomic Keyboard. Mechanical keys, as compact as HHKB, and has all function keys!