USB power is standardized, so anything that plugs into the wall and has a USB port on the back should work fine.

I regularly charge my phone with my Kindle charger and vice versa (and they even both use microUSB, so I can use the same wire too).

This is a real positive. My cell phone, my GPS and my in-car DAB radio all power from USB - I can charge and use them all with just one lead, instead of having a glovebox full of a Spaghetti Junction of different cables and connectors.

It also means that when one charger goes wrong, it's insanely cheap and easy to swap it out for a new one rather than having to look around for often expensive manufacturer-specific accessories.

Though some USB chargers output more than the standard 5V @ 500mA, up to 1500mA in my experience.

Amps is more like a maximum that they can supply kind of thing, not a how much they force out type of thing.

Yes they are! In fact any Mini USB charger is. You can also plug the included cable directly into your computer.