That tends to be one of the first questions people ask. It depends upon the definition of success within the context of the conversation. The main development sprint (for just the GUI rewrite) was approximately 700 hours. The current number of purchases via gumroad is around 150 users. After taking out gumroad fees that ends up putting me a bit below minimum-wage for the main development sprint (if you ignore any hours spent post-release). That amount funding has certainly been helpful in paying expenses (mostly rent), though it isn't at the scale where more full-time development is feasible. It was a good experience and I'd consider it successful in the context a one-time sort of event. Down the road I plan on having a much more detailed breakdown of the fundraiser, though at the moment my FLOSS writing time is being spent on preparing two submissions for the Linux Audio Conference (mruby-zest/rtosc).
Paid binaries are going to continue to be available for platforms where users are likely not going to want to compile for themselves (i.e. windows/macOS). This will help to continue to maintain support on those platforms as well as fund other aspects of development.