A number of weeks ago, Bluetooth tethering stopped working on my phone. I did a little bit of research, and discovered that a new USB wireless modem, the Sierra Wireless USBConnet Mercury, was coming out Real Soon. After the formal release date, I kept bugging all the AT&T stores near me, no matter where I was. They are always sold out, on "national backorder", and being shipped to stores a few at a time, where they were being promptly snapped up. Finally, when I called the closest AT&T store to my hotel here in Minneapolis, "Yes, we have two in stock." I promptly dropped everything, drove immediately to them, and managed to get them to sell me one without getting a phone number, or futzing with my account.
It does have a Mac driver, but it doesnt seem too crapware-ish (unlike what the Windows driver, which looks like a pile of ****, according to the manual).
It works! Works well, even.
Decent speeds, often better than what I get over WiFi from public hotspots.
So now crappy airport wifi with login pages, cafes that turn the wifi off, public connections that impose their own ads and popups, and client sites with paranoid overcontrolling outbound firewall blocks can just Kiss Off.