We study metabelian groups G given by full rank finite presentations xA | Ry M in the variety M of metabelian groups. We prove that G is a product of a free metabelian subgroup of rank maxt0, |A| ´|R|u and a virtually abelian normal subgroup, and that if |R| ď |A| ´2 then the Diophantine problem of G is undecidable, while it is decidable if |R| ě |A|. We further prove that if |R| ď |A| ´1 then in any direct decomposition of G all, but one, factors are virtually abelian. Since finite presentations have full rank asymptotically almost surely, finitely presented metabelian groups satisfy all the aforementioned properties asymptotically almost surely.