We had our house valued through a few agents, with some variation between agents. Having rejected the so called bigger agents (mainly because they charged higher fees and seemed to exaggerate) we relied on a friend's recommendation and went with Austin Chambers.
We were pleasantly surprised to have two offers of a holding deposit from the first week viewing and have tenants in place within the month. They've also been very helpful through the tenancy when needed so far.
Hopefully they'll keep up the good work.