The students actually make it a fairly expensive place if you're a couple/family. You're competing against 4/5 people each paying £350/month (or their HMO landlord).Marchmont's quite nice, but it wouldn't be student central if it was a particularly expensive place to stay.
Worse still some landlords have mutilated the generous proportions of the flats to subdivide into additional bedrooms. Kitchens that were a sizeable room in their own right are divided into a bedroom and small windowless kitchen. Box rooms are advertised as bedrooms despite being barely bigger than a bed. A lot of these flats were built with two reception rooms, which are turned into long narrow bedrooms.A particularly ghastly example is this.