OTOH if you have no access to full keyboards, this is better than nothing...
Sorry, dude, but I must disagree. I've known several people who've gotten false impressions from these. Theres' a big difference between how one switch feels with one finger, and how a bunch of them feel with
all of your fingers.
In addition to convincing you that you like certain switches, these can convince you that you
don't some you actually would. A couple of years ago I tried a Cherry MX Black in a tester, and from that point on I never considered them. Then recently, I was trying some demo boards at a PC shop and kept coming back to one that felt better to me than all the rest. Surprise—it had Blacks. I didn't realize that with a bit more resistance, it's much easier to type in the "sweet" zone between actuation and bottoming out. (Cherry MXs actuate 50% through their travel, so any pressing you do beyond that is wasted time and effort.) All the tester had told me was that Blacks were stiffer than the others.
Anyway, please don't get the idea I'm criticizing you for sharing an interesting deal—that's always a generous thing to do. I just thought I'd throw in my 2¢ about this particular kind of item. Obviously there are lots of opinions.
Plus this one does seem to be numpad-shaped, and may very well lend itself to a creative individual doing their own wiring to make an actual numpad... Also it can provide one of a number of switches that you can keep as spares should you need to replace a switch in a keyboard in the future, and do not wish to spend time and money purchasing a switch from a retailer, or don't like imposing on the goodwill of fellow GH members... They also make great display boards for a smallish number of artisan keycaps.
Indeed, all good reasons to consider one of these even if you don't agree with the "tester" idea! Cheers, A.