Overall great, with some potential still to be realized
The form.io engine is great in many ways, but here are some of the less-than-ideal parts about their product that keep me from saying 5-stars: 1) The pricing is not very flexible, and in our case, somewhat high. We only use the UI elements, form designer and pdf-filler but none of the database/resources/submissions logic, but still have to pay for them. 2) The experience between the digital vs the PDF form filling don't entirely match. Certain field types aren't available on the PDF version, like address fields. 3) Lack of typing/documentation (TS declarations or JSDocs). If you decide to use the native FormIO components on your site, there is no built-in guidance about the properties/functions you can access. 4) Inconsistency with the support team. There are some absolute superstars in their CS team (shoutout to Jordan & Remy) who understand and resolve your issue in a single shot. At other times however, I've ended up in 2-week back-n-forths with their support team only and not getting a resolution.