First, I'm a free player, so I get to do one raid a day unless I buy passes (which I do occasionally). Given that, I want my one raid to be a good one. And with the pressures of work and real life, I can't drive all around checking gyms for the best raids.
I've tried to use GymHuntr to locate good raids (Machamp, Tyranitar, Legendaries), but it's kind of wonky - sometimes I'll scan, wait two minutes, and still have no information about the gyms in the scan area.
Those of you who are lucky enough to live in urban areas and be able to see 10-30 raids from where you are, that's great for you, but please don't get high and mighty about using tools to help play the game. It's a commitment to go to a raid, and I don't want to make it stupidly.
What are people using besides GymHuntr, or live info from Messenger or Discord?
On you suggestion, I used tried that site. It is superior to gymhunter in some respects, but it does not identify the type of raid boss, only the tier. So for level 5 raids, no problem because the raid boss is a function of geographic locations. But for all the other levels, it appears useless if you are looking to battle a specific raid boss within a tier.