Core model
MLGS centers on recurring lead delivery plus a mailing system. Systeme.io is a software platform for building funnels, websites, email campaigns and related online-business workflows.
Lead source
MLGS supplies a specific business-opportunity/internet-marketing lead stream. Systeme.io provides tools to collect and manage leads you generate through your own traffic and funnels.
Email workflow
MLGS includes a simple built-in mailer and an export option. Systeme.io is designed around broader funnel and automation workflows.
Who should investigate each?
Investigate MLGS if the supplied lead stream is the feature you actually need. Investigate Systeme.io if building your own funnel and controlling acquisition is the central requirement.
Key trade-off
MLGS reduces the need to source every lead yourself but ties the model to its supplied audience. A funnel platform gives you more control over acquisition but leaves traffic generation to you.