The Epic Malibu I sent to Roger Caffin was, I believe, the same material formerly used by Black Diamond for tents. It is a milky yellow and appears identical to the tent material. It is a ripstop polyester, not a nylon, and does not sag under the conditions that silnylon sags. Yet it has a high bias stretch.
Roger's comments were as follows:
"Two yellow EPIC Malibu fabrics, both seemed to breathe slightly as expected.
Dry at 10 kPa, but around 15 kPa the surface suddenly erupted with
drops of water everywhere. Increasing the pressure beyond this simply
increased the flow everywhere. This is normal for EPIC. The big
problem is when the fabric gets slightly dirty: the surface tension
effect then dies."
15 kPa is around 1500mm HH, which isn't bad; however, unlike many silnylons that just leak a little after a few drops appear, the Malibu completely wets out and becomes useless as a protective water barrier when it fails.
For clothing or sleepwear, as opposed to shelters, the material is much more likely to become contaminated by oils and fail sooner for that reason. It also may be that the material is more water resistant when suspended under tension on a canopy, as opposed to wrinkling on a garment. If I had a choice of this material and a high quality DWR for a shell material, I'd go for the latter due to the lighter weight and greater vapor permeability. Tried a couple Epic treated pullovers from Wild Things and found they did not breathe well, and wetted out in severe rain above treeline in the Presidential range. Don't think this material was Malibu.
For tents, however, the Malibu may have some value. It obviously has to be used in conditions where it can be kept clean. I've still not decided whether to try it on the next tent. Cuben is much lighter, but due to the lack of elasticity and weakness at sewn seams, more difficult to work with. The Malibu I have came partly from OwareUSA and partly from Thru-Hiker. It was the second generation material used by BD, with a slightly shiny surface on one side due to calendering. (Also had some first generation material from OWF that is not calendered.) The 2d gen material weighs between 1.8 and 1.9 oz/sq/yd, not the 1.7 oz often given for Malibu.
I tested this material in a plastic embroidery loop over a weighted pail on an outside deck a couple years ago for over a month during a very rainy fall. After several weeks, it did finally wet out after over 12 hours of hard rain, but did not allow much water to collect in the pail. Also tested it later with a garden hose nozzle pushed against it on high, and water did not penetrate it.
In a more recent test Roger did on another fabric, it tested at 15 kPa initially, but when he repeated the test, it leaked at much lower pressure. This might happen with the Malibu also if subjected to repeated testing. I plan to get a tester going this year, and have toyed with the idea of just leaving the pressure at around 1500mm HH for a long period, rather than just keeping raising it till failure.
Lastly, there is some question about what Epic Malibu is. Ordered some more recently from OWF, and it did not resemble the yellow in weave or texture. It may be that the term is being used for a variety of different materials with the Epic treatment.
Hope this is helpful.