Hi JamesCam,
The conventional wisdom, which I support, is that the hard pavement is better, provided its LCN is up to the job. The last thing you want is the wheels burying themselves into mother earth. Even on a smooth touchdown, the tyre pressures (over 200psi) of a large aeroplane mean that the latter is inevitable on grass, and this was the cause of most - if not all - of the damage to Echo-Echo.