I now feel confident buying a pagebuilder license, using Gutenberg has actually convinced me to do so!

I've never been an enthusiastic page-builder user, at the very most been forced to extend Visual Composer for client sites. I've made large site themes & plugins from scratch (by necessity) but certain clients are actually a good fit for pagebuilders. Some clients have fussy commisioning processes, low budgets, and a need for "rich layout editing". So, I've been looking forward to Gutenberg since it was first announced as it would certainly help me sell sites (to those clients).

The current Gutenberg implementation has made me look around at the pagebuilder landscape to evaluate the competition. I was surprised to find that one of the competitors really was sleek, fast and intuitive with a lot of tools which would help me. The UX and UI are good, it had a decent API and extendibility. Importantly my annoying clients are seduced by it, making my job easier. In comparison to that builder I find Gutenberg buggy, unlovely and unreliable. I cannot see Gutenberg replacing a pagebuilder in the next 2 years, based on the current UI, and UX.

A single simple example of "unlovely / unreliable": Setting the width of the WP-GB editor. Most clients want it full width because it is very narrow. There are docs for making the editor full width, and they are wrong. The issue is tracked (#9894, #10067) . Editor width setting used to work, it broke a couple of months back, the docs remain incorrect.
A small issue, it could be dismissed as unimportant, but compare the user experience (and agency experience) versus a competitor page builder. When trying to deliver a "rich editor" solution to a fussy client these sort of issues compound to create a storm of costly dissatisfaction.

The user experience is worlds apart.