The eM2 was a perfect fit for the Mac mini. The bag opened up enough for easy insertion and removal of the Mac, but the sides are such that the computer cannot accidentally fall out of the bag... even when fully unzipped.
The eM2 also have a side pocket for things like the AC adapter and cables. Everything we needed and nothing we didn't.
So, if you need to constantly transport a Mac mini from place to place, we can heartily recommend this eM2 case from Tom Bihn.
They also have cases and bags for many other tasks. We found a perfect bag (BrainCell) for our smaller laptops. The case came with two keyboard cloth (to keep the keys from scratching the screen).
Along with the BrainCell, we also got the non-slip TerraGrip Strap. The strap was made with nylon webbing with the shoulder padding molded onto the strap. The swivel clips are nylon hooks with metal loops. The best part is they stay on your shoulders!
Go to the Tom Bihn and check out all the other bags in their line. You will see some of the most well thought out gear bags available.