I sold my house last year. I had three agents round, with a 20k difference between top and bottom valuation (range - 155 - 175k). 2 of the agents gave me the hard sell and were utterly odious. The third agent looked round, told us what it would fetch, said not to take offers, and would wait for our call - no hard sell. He also had the lowest commission. We gave him the job and the house sold for full asking in 3 days.
Moral of the story - work your way through the local agents until you find one you don't want to punch.