Yeah, their distribution kinda sucks...

I was looking at getting mine from Germany but the postage was going to be more than the chips were worth... but they were looking for leads on companies in Australia who could act as distributors for them, & agreed to swap me a couple of chips for some suggestions on who to try.

So, you may be able to get some for review purposes.

Can't hurt to ask.
As far as cost effectiveness... I think the chips I have (digital directions + 8 buttons) were going to cost about the same as a gamepad, once you add the other required components. The more advanced chips were not much more costly I believe, which may make them cheaper than the gamepad (or keyboard?) equivalent.
Also, some people may prefer having a chip with circuit diagrams so they can build their own interface, making a PCB as small as they like (within limits of the circuitry), rather than hacking a pad. That's certainly what got me looking at them in the first place.
(Like I said, I still haven't put mine to use, so can't comment on the end result.)