Yes, used Liteloft for a winter bag, and it was suitably warm for less weight than other synthetics. Did not have Thomas' breathability problem, but sewed it into the bag without any scrim. Liteloft is a batt material, not a dense, thin material like most Thinsulate.
Also had a YakSak from Yakworks, that used the regular dense, thin Thinsulate.
Worked great for about a year, then for some reason lost its insulating properties. Strange, because the material does not rely on loft, so there was no loft to lose due to compression. It weighed about two pounds and used it comfortably in the old Tamarack shelter just below Killington (VT) Peak in the winter when it was new. Well below freezing. But after the year, it was not warm even around freezing in warmer seasons.
For the same insulative value, both the Primaloft and Apex seem to be much warmer for weight than regular Thinsulate.
Was thinking of filling compartments in a bag with Thinsulate LiteLoft (not regular Thinsulate) instead of down, to eliminate any compression of the batts at stitch lines. Based on Thomas' post, will have to rethink now, and consider Apex or Primaloft. Maybe look at Roger Caffin's experiments and come up with some kind of tests for insulative value – but even those would not address the breathability issue Thomas raises. Thanks for the info.
P.S. Asked OWF a couple years ago why they discontinued LiteLoft, and they said because it had become too expensive. No mention of breathability or function issues.
