Core model
MLGS is centered on a supplied lead stream and mailing workflow. Kit is designed around creators building and nurturing their own audience.
Lead acquisition
MLGS advertises daily delivery of business-opportunity and internet-marketing leads. Kit provides forms, landing-page and email tools rather than a bundled daily lead list.
Email marketing
Both can be part of an email workflow, but Kit is built around deeper audience-management and creator-oriented publishing workflows.
Best comparison question
If your bottleneck is getting an initial stream of relevant contacts, MLGS addresses that directly. If your bottleneck is building an owned creator audience and managing subscribers, Kit addresses a different problem.
Important caveat
Do not treat a supplied lead count as equivalent to an owned audience. The downstream value of either model depends on engagement, fit and your marketing execution.