I refuse to pay the extra $130 for the Wi-Fi version ON TOP of paying an extra data fee I already pay for my iPhone 3GS.
So I plan to just use my jailbroken iPhone as a Wi-Fi hotspot with MyWi
I presume you meant 3G, because WiFi in that sentence doesn't make sense.
I am doing the same. I have it running with MyWi on my JB'd iPhone. Apparently tethering like this is perfectly fine with the European cell companies and that's where I'm headed for a while.
I bought it for an upcoming trip to Europe. I bought the Camera Connector Kit to be able to read SD cards and not have to buy a laptop (I have a work-provided laptop that I'm not bringing because it's a 17" desktop-replacement ~8lb behemoth of a laptop).
As far as it's usefulness, I bought it pretty much entirely to entertain my children on car trips - watching movies and playing games together - for myself to use as a mini-laptop while travelling, and as an e-book reader. In reality, I use it for these things, but I also tend to use it a lot more than I thought that I would. I have it plugged in the kitchen next to the phone and everyone in the family has been picking it up and using it to check email. My wife used it as a cookbook a few nights ago. I was sitting down at dinner trying to remember if we paid the credit card bill and quickly looked it up online in a few minutes. It's been handy to have an always on device sitting around in the kitchen - much more than I would have thought.
So far so good. The screen is very bright and colorful, the battery life is really impressive, and it feels really fast and responsive when you use it. I'm pleased with my $500 (+$30 for the camera kit) so far. I could live without it, it's not a revolution, it's not magical and it is just a big iPod Touch... but it's been useful. I know people who have paid over $1000 for an in-car entertainment system. Compared to that, an iPad looks cheap.
I couldn't find it in any of the local stores either, so I had to buy it online. It shipped in 5 days... but from China and then took a fair bit longer than I thought it would to get here. As far as their "no cash" policy - given prices on Ebay, it makes sense. Anyone wanting to pay in cash should be able to find a friend with a credit card to help them buy it.