Is it the Helix framework you are concerned about or SP Pagebuilder?
There are no known issues with the Helix Framework/Helix Ultimate Template - you should remember to create Bootstrap 4 based layouts in EasyLayouts since the Helix Ultimate template is based on Bootstrap 4.
SP Pagebuilder is more problematic - if you were hoping that EasyLayouts could customise the output of the articles addon (for example). This isn't possible at present, since SPPageBuilder has hard coded the output of the articles addon. It MAY be possible for EasyLayouts to override this if its important to your requirements.
You can easily switch EasyLayouts off and on again via a special module on the demo site and can also access the backend to experiment with the layouts. The demo resets every hour so bear in mind that the demo looks a bit odd that someone else may have changed the layouts before you viewed the page.