To answer that question, firstly let me explain what 3D is. The correct description of two images to be viewed to create a full-depth perspective is known as 'stereoscopic' or shortened to 'stereo'. However, with the popularity of IMAX 3D cinemas and the current trend for 3D films and television, it is now more generally known as '3D' to which I will now refer.
True 3D is created with two lenses, spaced apart usually by the average distance between human eyes (64mm) but slightly more or less isn't significant. I use three such cameras which will create a completely full-depth image.
Remember the old CRT televisions? It wasn't so long ago we all had them, but now flat screen TVs seem to have taken over. The same could be true with 3D televisons - they will most likely be commonplace in not so many years from now. Remember, have your photographs taken in 3D now and in the years ahead you can look back and be thankful you had the foresight. Digital conversions from 2D are only a compromise and will not work like a true stereoscopic image.
To create the full-depth perspective each image MUST only be seen by the relevant eye. To this end there are three alternatives for digital viewing. The two most common require the use of special glasses; one type have polarising lenses which, when aimed at a multi-polarising screen, will differentiate left and right images respectively and the brain will 'see' exactly as you normally see with your own eyes. The other type uses a special 'flip' LCD screen over each eye, alternating at the same rate as the left and right images on the screen. Since we are used to television using multiple frames per second to 'fool' the brain, this works slightly better than the polarising system. There is a third method but as yet the televisons are extremely expensive. They use a special grid in front of the main screen (called a parallax barrier) and work similar to lenticular pictures (where you move the picture and see different images according to the angle of view).
2014 Update: New technology is making 3D an easier world to join. Now I have sourced high-specification parallax-barrier tablet PCs for free-viewing 3D (NO glasses required).
These are full tablet PCs and not just viewers, so you get (2013 specification): dual core CPU, quad core GPU, 16Gb on-board storage (can upgrade a further 32Gb with microSD), 1Gb DDR3 RAM, IPS 9.7" panel (same size as iPad 4). Android 4.2.2 operating system, use Google Play market apps or other downloads. These will play full 3D stills and video. See 3D prices page for cost.
Answer to the question: regardless of which viewing method you choose, true 3D is like actually being there. My proficiency in wedding photography combined with my wide experience in 3D photography [stills and video] will ensure your memories of the special day will make you feel like you are right back there again (or, for those not present at the time, be absolutely the next-best-thing to it!).
For some sample 3D photographs, please see my website: 3D.RoySmyth.com