The insulation they use is called Combat Climashield, and it is my understanding (but don't quote me), that this is a very similar insulation to the "Lamilite" that Wiggy has used in his bags for many years.
But to answer your question, yes, reputation is what urged me to buy it. I got to know Mel Terkla, the head of Kifaru's military division, many years ago (before he went to work for Kifaru). Mel and the others at the company are stand up people, and hugely respected in the "tactical" and hunting gear world. I've owned a large amount of Kifaru gear over the years, from packs to pouches, etc. Their gear is bomb-proof to a fault. Kifaru recently entered the ultralight market with a few packs and these sleeping bags.
As a side note, I want to make it perfectly clear, I am in no way associated with Kifaru. (Haha) I'm actually a law enforcement officer. I'm simply a very happy customer of theirs, although I have zero experience with their sleeping bags, which is why I'm asking for input.
Oh, PS- The compression sack thing might not be a typo. I Have one and they are EXTREMELY light. It is made of the same parachute type stuff that the sleeping bag is covered in, an almost see-through, plasticky type material.