Go for as many Hz as you can get. The 3D files I have d/l have never worked. There must be some code missing because the discs always work. "John Carter" is quite good. The demo discs are recoded in a special way to exaggerate the effect reaching out of the screen ( similar at exerienced in the cinema pre-views) whereas most stuff seems to create a feeling of depth, reaching back into the screen.
In my opinion active is better than passive as the latter uses a polarizing system which affects clarity but you don't have expensive, battery operated glasses.
Actually there is not much good 3D content around, even OSN seems to have given up - the HD broadcasts are more interesting. I bought a SONY and am very satisfied with it but whilst the panel is Samsung and you can adjsut the sharpness, it seems to be sharper on their Samsung sets.
You get what you pay for. Good luck, but recommend you get a player and suround sound system to maximise the enjoyment from your investment.