I was expecting to use PB when we last moved, but in the end went with a local agent as we got the usual 1.25% reduced to 0.8% (I've not paid more than 1% on our last 3 moves).
It wasn't a high value home either, I think the agents saw how well we had prepared the house (even creating info sheets for viewers) and were prepared to reduce their margin. In practice their rates are impacted by the time wasters, people over pricing their properties etc which PB aren't affected by due to the upfront and viewing fees.
The agents handled several full days of viewings and although I still think they were fairly well paid, it wasn't bad value compared to PB for that house at least.