My first choice with regards to choosing a letting agency would be Belvoir. They are always very professional, extremely helpful and always available should any questions or problems need addressing.
They carry out regular inspections but are very considerate to my home. Due to me working unusual shifts I can't always be available, but am more than happy for them to carry out the necessary checks anytime I'm out.
I would happily recommend them to anyone looking for a professional service and great property to rent.