What are some alternatives?
When comparing Landing Pages by Viral Loops and Landing Harbor, you can also consider the following products
Landing Pages in MailChimp - Easy to build, custom landing pages for free
Generator by DesignModo - Easy way to make a landing page for your startup
Carrd - Simple, responsive one-page site creator.
SaaS Pages - 900+ Screenshots of the best SaaS landing pages
The Landing Page Cookbook - A guide for makers who want to create better landing pages.
Viral Loops for Startups - Virality for startups made easy 💪