As convenient as USB charging is, traveling a lot gives me the problem of available outlets for all my devices. I've had some success with some dual port ones that can handle my Xperia Tablet Z and my Xperia Z1 Compact... but nowadays, even phones need 2.1A of power. So those just won't do anymore.
A quick Google search led me to Anker and their 5-port USB desktop charger. It's quite simple. 5 intelligent USB ports. 2.1A on ALL ports... ALL THE TIME! Sweet! The intelligent chip inside the charger regulates the amount of power. Handles tablets, phones, phones in use, etc. Charges all devices at full speed.
It's about the size of the Apple Macbook power adapter so it's easy enough to carry around and won't add any significant weight or bulk to your bag.
So far, so good. Most of the time, I use up about 4 ports. Leaving one free for a friend or any new gadget I may buy in the future. I'm quite happy with it and their customer support was quite quick to send an email asking if I was happy with my purchase.
If you have more than 3 USB devices that are taking up outlet space, this is a definite must-have in your kit!