Lead Generation for Wealth managers to meet High Net Worths

We work with a great company called Outbound Solutions who do all of our lead Generation - Very focused approach where they connect us with Owners of Businesses and large corporates.

They give us a small number of quality appointments each month. My question is - has anyone had success with any of the more call centre type companies who give you quantity over quality.

Definitely some cheaper options out there but wondered if they are a waste of time?