If the Altima was a four door, and you paid less for the Suburu; I'd consider it a draw. The Altima is 350 or so lbs lighter than the Impala; but the interior dimensions are somewhat similar.
Availability is always an issue at "local editions".
One factor I always try to consider is what is the smallest vehicle that will get the job done?
But now you know to try to stay out of the Suburu; your healthy back is worth more than that.