My friends and I used this agent to rent a student house from in 2010. Whilst the house was adequate, their handling of the entire system was unprofessional and infuriating.
The major point that got me was their handling of returning the security deposit paid at the start of the year. The landlady tried to charge us far far too much for minor repairs, which we questioned and queried with the landlord through an excruciating process with Mansons. We were patronised and lied to at every stage, and ended up getting back less than what we had agreed. The letting agent should be impartial to both sides, but they were completely backing the landlady in her efforts; perhaps they get a cut of the winnings...
I would never recommend this agency to anyone, not even to rent the smallest, cheapest shed. There are loads of letting agents in Newcastle, dont go for this one.