I've just done a little research to see if there's anything in writing about how the show is faring. This is what I've come up with:
IMDB Ratings
DreamWorks Animation Financial Report
Netflix Financial Report
Now, I don't know anything about the credibility of these sources, but, if what they're saying is true, then I have a few points to make (mostly) in favor of the show's success:
1. The IMDB ratings for the show indicate that it is a success to the viewers.
HTTYD has an 8.2, and
RTTE has an 8.5, which should mean that people actually like the show and that there will probably be continued viewership when the next set of episodes is released. That said, the number of reviews for
RTTE is significantly less than that of the movies or
RoB. That could mean that the show actually isn't as popular, or it could just have something to do with the fact that the Netflix-specific series is relatively new.
2. The DreamWorks Animation report says: "Third-quarter revenue from DreamWorks Animation’s TV business more than tripled in the period to $51 million." This includes the shows for
Madagascar and other spin-off series on Netflix, but, since
HTTYD is one of the most popular DreamWorks franchises, I think it can be reasonably concluded that a significant bit of that profit came from
RTTE.
3. I think that the strongest evidence for the success of the show comes from the Netflix report.
Race to the Edge is listed as one of the new programs that has helped significantly boost Netflix's earnings. If you consider how many shows and movies are brought into Netflix every quarter, and if you look at how popular some of the adult shows are, then you can see that it's a huge deal to be on that list.
Even with all that, though, I can't find any specific numbers as to how many people watch the show or how much it has benefited DWA so far.