I wouldn't say that it is a collectable per se unless you happen to value something in particular about it. The AEKII was not really uncommon, but that one would be less common, but again unless there is something specific about it you happen to fancy I probably wouldn't drop anything for it.
Indeed you would have to use a converter to use in on a PC, I think there was a converter (kinda hard to find now) called the Griffen imate (sp? try a search here on geekhack for it, I am sure it's somewhere).
Someone also mentioned at one point a device by Belkin that could/would do the trick. I think the prices run between $15-40 (i think). Belkin being the cheaper one I believe.
The switch is ALPS and the keycaps are nice and thick with a dye sub print. Pretty durable. Like many older keyboards they were very suseptable to yellowing (the cases a bit more than the keys). They are usually known for the dampened slider, which keeps the key stroke a little bit on the quiet side for a mechanical board. The switch is tactile but not clicky, and some mod other ALPS switches with these dampened ones.
I hope some of that info helped =)
p.s. It was my first mechanical keyboard in 1992 along with my first compy Apple IIci. (although different layout)
good times =)