As a small growth hacking agency, Closely is one of the best options to run LinkedIn outbound marketing campaigns. It's relatively cheap compared to competitors and has an excellent interface and good reporting dashboard. It might not be as advanced as some competiting tools (that offer: auto likes, group campaigns or long delays - more than 30 days), but instead, it does exactly what your client wants. To grow their network and generate leads.

I would definitely recommend considering price and quality.