There's a bit of confusion out there about ports on the new MacBook Pro. They are all USB-C, a smaller version of USB-C that lets you plug in with either side of the plug "up" and no problems. It's both smaller and better than the USB-A, the rectangular plug that came with the original iMac and is now pretty much everywhere. I had the USB-C port on my MacBook and I liked it. Better yet, the usual assortment of dongles and cords are now available.
The wrinkle is that with the new MacBook Pros the port isn't just USB-C, it's also Thunderbolt 3. Thunderbolt 3 is a wicked-fast new Intel protocol that allows you to push an enormous number of 1's and 0's through a cable. Thunderbolt 3 is the reason that the new MacBook Pros can drive two external 5K monitors. Whenever Apple next updates the iMac, you can fully expect it will also be loaded with Thunderbolt 3 USB-C ports.
The trouble is that not all USB-C adapters and cables are Thunderbolt 3 compliant. If you're getting ready to board the USB-C Thunderbolt 3 train, I recommend this article by Glenn Fleishman at TidBits where he explains everything in full and makes some product recommendations.