I'm going with Owens Corning shingles and their licensed (or whatever) installer after getting 3 quotes. My primary concern was, ok, so you (the installer) are giving me a xx # of years workmanship warranty. How do I know you'll still be in business if the time comes and I need warranty work? Owens Corning warranty says that if the original installer is no longer available, the closest installer will come out for the warranty work.

GAF is fine, but they just spend $$$ on marketing and the big box stores use them. I'll pass on that though.

Just Google, "new shingles reddit" for all the first hand info from customers and installers. The rep who came out for the quote provided all the info I was going to ask based on my research. Everything he said is everything I wanted based on what I learned. The other 2 quotes, yeah not so much. Be wary of a roofer who also wants to replace your gutters, "just because you might as well at the same time". If your gutters don't have issues, don't replace them "just because". The quote I chose didn't say squat about gutter replacement - because they don't need to be.

Here's one search result to get the OP started:
https://www.reddit.com/r/HomeImprovement/comments/7qurnm/what_to_look_out_for_when_getting_new_roof/

To ensure your neighbors keep up their house maintenance and their property doesn't have rusted cars sitting on cinder blocks; grass up to their windows; and also don't install white shingles that stand out like a sore thumb.

You can't choose your neighbors, but can at least know they aren't going to be dirtbags making the neighborhood look like trash.