Hello all.
Whilst I wouldn't like to get into a debate as to which is the best, I would think if the paper pots are wet when put into the ground, they will start to disintegrate (decompose) sufficiently quickly for the roots to be able to develop. The important point is to ensure the paper pot is planted so as none of it is above ground, as if it is, it can draw moisture from the ground.
Regards
Bluecar