I think overall most experts agree the viewing experience on Passive 3D TVs is faster, more convenient, comfortable, and natural. The problem with these Passive 3D TVs is that they essentially cut down the visual information presented to each eye in half which Active 3D doesn't do. Text looks sharper, details have less artifacts with Active 3D technology which presents 1080p to both eyes via active shutters.
A 4K Passive 3D TV can present 1080p image to both eyes with all the other advantages of a Passive 3D image. Such an advance would be very notable when screens are larger than 60".
Although 4k is all the rage, I'll hope for a 4K Passive 3d TV soon.