I use Lemlist. I love it, and it has a native integration with Clay. You can buy pre-warmed email boxes, so you aren't sending from your main domain. I have 5 boxes, and I am sending about 2k emails a month. Fully automated. Clay to find, enrich, score and personalize, then add a column to automatically push to a Lemlist campaign. If you set it to auto-run it can pull in new leads daily or weekly, and any lead added to those campaigns automatically enter the sequence. Set it up once, and it runs on autopilot. I haven't tried instantly, but I've heard it's very similar. Lemlist will also automate LI connects and profile views. So if you do a 4 or 5 step sequence you can do 2 emails, a LI connect, another email and a LI view for multiple touch points over a longer period of time.
