Justin is not a waste of space. Becca is the one who couldn't even be bothered to even go looking for a job until today! Yet she's moaning about money and at the same time she's telling Justin not to leave school! The solution to this (i.e her getting a job) should have been done weeks ago.
As for Jake and Becca being a good couple. I think they were dull and an awful couple. They have both lied and cheated on each other and Becca obviously cheated as things wern't right with Jake.