Cience provides what could be described as an "SDR Team As A Service". They handle the entire outreach stack - from procuring the data, through to securing appointments and booking meetings. Cience combines their own proprietary tools that harness AI & machine learning, with well-trained individuals to manage your campaigns.
If you can afford the higher price point, they will take the entire process of procuring leads off your hands!
Yesware is an add-on for Outlook and Gmail that gives sales professionals everything they need to prospect, schedule meetings and follow up.
There are very few bugs and their email tracking is on point. You'll always know when someone opens or clicks a link in your email!