[looun]

Hmmm, is the Pi2 really that bad?? Seems surprising to me that no one would have commented on it...

Of course not. The picture quality is excellent for 2D and 3D (the quality of each will be the same) as is frequently commented on.
If @flipmode009 has an issue, then please open a thread in Pi forum and provide information there (e.g. comparative screen shots).

It is possible some settings are degrading picture quality. The obvious one is not enabling "Use full HD modes for 3D", which would result in losing half the resolution.
You could lose some quality by having overscan enabled on TV and scaling the image in Kodi to compensate. Not using a 1080p HDMI mode, obviously.
If colours are too light or dark there may be a mismatch of limited/full RGB range of HDMI, but that would be unusual. It can however be forced if display both doesn't respect the information in the AV infoframe and doesn't use the usual defaults for CEA and DMT modes.

i suppose him talking about:
- Q5 have Excellent PQ thanks to included Image and Display Processing (Imprex
Processing Engine)
- Pi2 have also a excellent picture quality

but in some case ( especially with projector and plasma TV) Q5 Express engine have WOW effect with picture quality ,also because can be change quality setting LIVE ( pop-up menu ) for different parameter (Optimal, sky, scenery ecc. ) to match best movie quality.

In the end Q5 it's not "better" Pi2 player , it's only different.