I have one of those. (The IBM PS/2 model P70, as pictured in the second post.) Unfortunately, they don't have batteries in them. I even bought someone's old desktop 386 in order to get a 387 to add to it, so as to make it a more powerful computer.
Of course, the original poster was really asking about what current laptop, compatible with today's software and operating systems, has the best keyboard. Sadly, I don't think there is much choice, although the scissor-switch keyboard of laptops is somewhat better than the usual rubber dome for desktops.