Hey @askar! You are quite curious . As far as 2G and 3G go, here’s an excerpt from our recent Kickstarter:
Because these are low-bandwidth products, the speed of 3G won’t make much of a difference. The biggest issue to keep in mind is that the 2G network is going to be retired in the U.S. in 2017. Therefore if you have a project that you want to work for more than a year we recommend the Electron 3G in the U.S., whereas the Electron 2G is probably fine in Europe (for the foreseeable future at least).
I’m not sure about the sunset date of 2G in Japan, but if you would like to guarantee that your product will work for the foreseeable future, it may make sense to go with the 3G Electron.
As for projects with the Electron, there aren’t any yet! We are still in heavy development mode for the Electron and haven’t released any to the public. If you’d like to see some potential examples of projects:
Hope this helps!