Ask HN: What is your favorite mobile hotspot?

xcomglobal makes an expensive but really neat product for traveling abroad to more exotic locales, but what are your favorite choices for local use as well as international? I'm looking for a cheap option for major U.S. cities and perhaps Canada/Mexico as well. I'm intrigued by the clearcut payments of yourkarma.com.

Smaller data packages are fine; this is mostly for dev while traveling.