The best thing about popileads was how they were able to integrate with my various systems (Airtable + Mailchimp).
It's also super easy to add new fields/customer information if needed! I wish there would be an option where we could edit certain customer info after it has been imported but other than this all great so far!! We've had no issues when using them as part of a marketing automation strategy - getting customers into their system & managing communication across channels via email campaigns etc.