Geoges,
You should try one, either a Hassie 22mp or a P25...
Jim is quite right about this, it's the size of the pixels, the fact that the back seems kind to older lenses, the smooth tonal graduation is just really really great... In all it's just 'different'...
I don't ever plan on selling my P25 and to add to that you don't see very many for sale at all compared to say a P30 or a Hassie H3D with 30mp back.
If you can Georges... just go and try one or play with one..
Good luck Jim..
Steve