I had a SRAM S7 on my Swift Folder for a couple of years before selling that bike. I have a SRAM S7 on my Tikit and it's been there since September or October. It's a great hub for a folder with nice gear range, good shifting, good performance.

I also own two Rohloff hubs, one on a custom light touring bike and one that is going on our tandem. That hub's only real downside is cost. You can buy a very nice derailleur drivetrain for well under half the cost of a Rohloff.

For folders, especially 16" ones, internal hubs make tons of sense. Rear derailleurs tend to put the chain near the ground where they pick up snow, dirt, mud, and other stuff that you don't want in your drivetrain. An internal hub keeps everything cleaner and more reliable.