We are trying to decide which drip email provider to use for our proprietary outreach. We have heard decent things about several providers (Klenty, Replyify, Prospect.io, MailChimp, to name a few), but all seem pretty similar. Curious if anyone has a provider that they recommend?

For more context, we are not looking for anything too complicated. We have a good list of verified leads that we want to drop into the drip campaign and want to send around 5 emails to each lead during the campaign. We would value the ability to customize each email to the lead and the ability to easily beta test different text to see whether we can improve response rates.