We used WIX when we started, and stuck with it despite its restrictions and cost. Recently, we opted to move to Backdrop because it has a huge catalog of modules. We want to provide a more customized service to our clients, and the lmitations of WIX prevented us from being able to do that.
We rely on the Drupal 4 Ever team to keep our legacy Drupal 7 website running smoothly while we prepare to transition to Backdrop CMS. We are unable to move until certain critical Ubercart modules are ported - but as soon as they are ready we expect to have a fast and smooth transition