I use Netlify Forms a lot. It’s one of best form solution on the market. We even build those for websites that are not on Netlify yet.
There are few things that could be added/improved though:
Form submission confirmation email for form submitter with body customization.
Customizable body format of the email notification - I found that HTML table format is much easier to read, especially in long threads.
Remove “[Netlify]” from the subject - already mentioned here
Option to have uploads added to the notification as attachemnts - a big thing for all documents, etc.
Customizable “From” name of the email notification.