I park a few hundred of my own domains at Pimproll and even on my low traffic 404 redirects I've made several sales in the last month on domains that haven't otherwise resolved in more than 18 months because I've been too busy to re-point them somewhere else since the last parking provider sold out and turned $1200 a month of revenue into $100.
I'm their host - I not only trust my traffic to go there from how closely our teams have collaborated, I thanked them for turning 0's into something.
Brad