I'll concede that for the most active gives a better picture than passive (or Cinema 3D as its marketed as because passive sounds negative), but when you take into consideration the flicker and crosstalk problems active has, then Cinema 3D might well be a better option overall.
Add to that the fact that Cinema glasses are dirt cheap (literally pennies as apposed to about £50+ per pair), lightweight, don't require batteries (that could run out at an inconvenient time), or could go faulty (something I've seen a number of times with active glasses).
Another cool feature (which the Philips I linked to has) is that if you're a gamer, then you can get a pair of 'all left' glasses and a pair of 'all right' glasses and play a two player game on the same screen at the same time, but each player viewing a FULL screen!
There has also been talk of using the same tech to watch two programmes at the same time full screen, but that needs things like the sound sorting and twin tuners, so maybe something for future models. I'd love that, me watching the BTCC and the missus watching the Eastenders omnibus. Both in peace
Take those points on board, but try them both.