Over a year you would probably average about an extra 5 days away per month on the classic as you normally nightstop in Dubai both ways and they're doing a lot of regional flying in Asia now too. -400 rosters also more stable due better serviceability.
Flying better on the Classic and also allowances, so long as you don't p!ss it up against the wall in Wan Chai!
I'd say they're both good jobs, lifestyle better on the -400, work better on the Classic.