Personally I have preordered Start of May, and according to the schedule I will be hopefully getting it in the next 2-4 weeks my guess until the middle of July. So I wouldn’t expect any serious F3 reviews from users before August or even September, as you have to use a product for at least a month to get an idea of it.
Myself I have been a power user of F2 for Dentistry-Orthodontics for almost 2 years, and I am confident that at least surface finish wise and perhaps a bit speed wise, the F3 will be an update for my workflow. In addition if the printer has as advertised, parts that can be replaced by the user easily (compared to F2) when something fails, that will be a major update as well for those using heavily the printer (professionals such as myself).
On the other hand how much all of the above, will be of importance for you, in order to justify an update from an F2 to an F3, depends on what you use the printer for.
my 5 cents so far before even testing the Form3.