I use Prydwen for day 1 references on what stats to focus on when it comes to gear. My first choice, though, is
KQM when they release a character guide, since they tend to be more in-depth by comparison. However, they don't have info on everyone, so there's no builds for a lot of characters, and new characters can take a while (no Acheron, for example). KQM actually has updated their
Trailblazer (Fire) guide to include both the standard tank build and the hybrid warrior build that utilizes both offensive and defensive stats, while Prydwen still only has the tank build on it.
March 7th has 3 builds (Single-Target Tank, Freeze Crowd Controller, and Hybrid) while Prydwen still just has the standard day 1 defensive build.
I'll generally check if KQM has a build for a character, and if they don't, I'll check Prydwen.