The Transit Sling from Heimplanet is a smaller daily sling bag made with an interesting and nice feeling outer material.
Other Bags to Check Out:
A compact and more "built for everyday uses" version of their infamous GR1, this Echo pack from GoRuck is the kind of bag you buy once and use for decades.
A very sophisticated and classy take on the classic backpack, but with modern improvements for us tech-workers.
A very innovative backpack for either large daily carry or serious travelers who need one bag for both travel and daily carry. A great bag for medium size 1-bag travel category.
The Aer Duffel Pack is not the tool for every job, but for particular uses it just might be perfect for you.