To compare the two glasses we used the movie "Hugo," as the opening 5 minutes make an excellent 3D test. We compared both manufacturers glasses on both a Panasonic TC-P55ST50 and a Samsung PN50E8000, both set to the default Cinema modes for 3D.
Switching quickly between the two glasses there is a slight but noticeable difference in black levels. The image viewed through the Panasonic glasses seemed just a bit darker on the screens of both TVs. We're not sure if this difference is caused by the lenses themselves or simply by the Panasonic's fit -- the more closed design blocks out more ambient light even in our completely dark room.
There was almost no difference in color between the two sets of glasses, and the ghostly outlines of crosstalk appeared identical as well. Both varied depending on which TV we watched -- for the record the Samsung was superior in both areas -- but the glasses had a negligible impact.
In terms of fit, the Samsung glasses felt cheaper, were uncomfortable, and again didn't block out as much light from outside. These factors made wearing the Panasonics an overall better and more immersive viewing experience.
As far as longevity, neither pair is particularly immune to breakage -- we actually have a pair of each with cracks in the lenses that broke during shipping (better packaging next time, guys). The cracks expose the liquid crystal layer, which makes them useless. Moral of the story is: don't leave these out for people to stand or sit on. And if this is a problem, get a passive LG TV where the glasses are much cheaper and don't have the gooey LCD center.
Opinions are split on whether passive or active is the best 3D technology. Ty prefers passive as the interlacing artifacts aren't as annoying as the eyestrain that results from the crosstalk still found in active technologies. David finds those artifacts more objectionable than the mild crosstalk seen on the best active TVs.
If 3D is a secondary consideration (as it should be) here's what we'd recommend. If you're looking to save money on active glasses and own a compatible 2012 TV, buy a pair of the Panasonics for yourself to use most of the time, and then buy a few more pairs of these cheaper Samsungs for when the whole family sits down together. Just don't forget to put them away afterward.