Which award contests are worth entering?

Okay, there’s a ton of awards contests out there…some seem like “participation trophy” style….your book is “selected” and you get to cough up major $$$ to get the digital seals of approval to prove your work’s merit. Others seem more legit, but who knows? I’d love to hear from y’all about which ones are worthwhile entering, which are blatant scams (hello, vanity press!), and which ones you’ve personally entered and either regret or are thankful you did. Do tell, please! (PS I’ve already Googled it—I’m looking for personal experience testimonials pro and con specifics, please?)