With both our service and WP Ultimo you need to create template sites that serve as the master image on which all your customer sites are built.
But that's where the similarities end.
Many plugins that you might need are simply not compatible with Multisite (and, by extension, WP Ultimo.)
And WP Ultimo & Multisite can only scale one way - via larger servers.
Single Point of Failure
If a WP Ultimo or Multisite gets damaged, all your customers go down at the same time.
If your server provider where WP Ultimo is installed has an issue, all your customers have an issue.
Compatibility
With OpenSaaS, your sites are regular WP sites and compatible with a much wider range of plugins and themes.
Comprehensive Solution
And OpenSaaS is a hands-on service. With WP Ultimo you get the software - everything else is up to you including installation, configuration, scaling and more.
More...
There are many more differences but hopefully you get the point.
Bottom line is that OpenSaaS is far more flexible, has far more support and is committed to working with you to get you up and running.
In fact, our pricing model ensures that we only really succeed if you are successful.