I bought a Panasonic DMP-BDT310 Blu Ray Player [with 2D-3D conversion capability] to specifically function with my 3D TV [the LG 47LD950] which has no bells and whistles on it at all- albeit, the picture quality in HD is stunning with its 200Hz and "no-headache" Passive 3D Glasses.
I personally think that CGI-type animations and cartoon 2D-3D conversions work better than real-life footage. I played a short Shrek 3D DVD animation [approx 11 mins long] which was made to watch with those awful red-green paper glasses, but the Disc also had a regular 2D version of the short animation. On pressing the Blu Ray Players' 3D button- it definitely added depth to the animation. It's not earth-shattering, but it works well enough in a sort of depth-field view to justify the function.
I also tried the Kung Fu Panda Short too, which features CGI animation and 2D cartoon footage and the results were also reasonably good. This was not the case with say Inception [in the exploding dream scene of boxes and paving], where the depth is there but nothing seems to "come out at you" unlike Avatar or Tron Legacy DVD's which have ready-made 3D cues fit for purpose for example and look fantastic- to my eyes at least.
To be honest, with 2D-3D, at best- the DVD seemed crisper [upscaled] and vivid compared to the original 2D version, so I can imagine trying to re-view old DVD's that have been long neglected as 2D-3D might be an interesting way to refresh the retro discs. So I wouldn't dismiss it as a gimmick, it's not stunningly 3Dimensional, I would re-brand it as 3Depthy.
And at least for me, it makes no difference whether I set the 3D depth scale from -5 to +3, it still looks the same to me on both ends of the scale- it just seems to shift from left to right slightly. I don't know if anyone else had the same experience they could share with us.
But there is as far as I am concerned, a completely useless feature that exists on the Panasonic BDT310 which adds a [black, blue or red] blurry border to the edge of the picture to separate it from the bezel and allegedly create a deeper 3D image... in one word- fail. It just makes the screen footage shrink in size and makes you feel as if you've got creeping Glaucoma in your eyes and your edge-vision is gradually eroding away. No need for that.
Of course, there's no comparison to Real3D Hollywood films, but the kids seem happy enough with this cheap home alternative. I have noticed the ooing and aahing over the 3D effect stops a few minutes into the film and then they just get on with watching it like any other 2D movie.
With minimal 3D Blu Ray [or DVD] content available, beggars can't be choosers. These are early days and early innovations... so we put up with what we're given. Although I'm holding out for 3DH vision [3D Holographic!].