Between the three, the Panasonics were the most comfortable for me to wear, although their advantage over the Xpand specs diminished when I removed my prescription glasses. The Xpand glasses are heavier and tended to pinch the back of my head behind my ears more, especially when I wore my prescription glasses, and they perched further on the end of my nose. I also liked the blackout effect of the Panasonics' big wide temples for shutting out ambient light; the Xpand glasses were pretty good in this regard, and the Samsungs were, again, the worst of the three.
The X104s also have more extra features than the others, the most important being compatibility with numerous TVs and projectors. Here's the full list. I did not test compatibility with any TVs aside from the Panasonic TC-P50ST50 and Samsung PN60E8000 (see below), which both synced fine using the RF dongle.
The company also includes more accessories than do Panasonic and Samsung, namely a nice case, two different detachable nose bridge pieces, a cleaning cloth, and of course, a charging cable. Xpand estimates 35 hours per on a charge, five more than Panasonic. One end of the cable is standard USB, but the other is proprietary, and its matching connection on the glasses is where you'll stick the RF dongle.
Xpand also offers specialized PC software said to enable adjustment of the active shutter timings. I didn't test the software tweaks for this review, but here's a PDF explanation of how it works if you're curious.
The PC connection also allows for firmware upgrades. One recent update apparently added support for dual view -- where two 2D programs can be viewed simultaneously on the same 3D TV by two different viewers. I didn't test that feature.
I spent a couple hours watching my favorite 3D test film at the moment, "Hugo," in an attempt to discern differences in picture quality among the three glasses, switching glasses and views on the two TVs mentioned above. They looked close enough to one another to be indistinguishable in most scenes. Again, I ended up feeling that more closed view of the Panasonics improved perceived black-level performance, but the fat temples of the Xpand glasses helped a bit in this department as well.
Overall I liked the lighter, better-fitting Panasonic glasses best of the three, followed by the X104s, and then the Samsungs. The Xpand glasses make sense for people who need the flexibility to watch active 3D on more than one brand of 3D TV, or people who can save some money buying the X104s over the glasses they'd otherwise need to watch 3D.