It was ups and downs with this particular letting agency, they weren't great but they weren't totally awful either. Don't think the situation was helped by a stingy landlord who was hard for them to contact and wouldn't spend any money on the property. Repairs took weeks to get sorted, if they were at all (broken lavatory all year... good thing there was a second one; the central heating broke down three times in one year!).
The staff were friendly enough, but often didn't seem especially professional, and caused considerable frustration at times. They just didn't seem to get how difficult the poor maintainable on the property made life!