In my frustration and ranting the other day, I might have made it sound like I thought the top MM romance writers were all crap written by amateurs. I definitely do not think that, and hopefully no one took it that way.
In an effort to atone for the negativity I put out, I want to give a shout-out to MM romance writers that I think are great. These aren't the only ones, but they are the ones that most prominently pop into my mind. They have true mastery of all parts of the craft: from prose style to pacing to structure, character, and tone.
I'm also picking these authors because they write "pure romance." By this, I mean the standard romance beats are there structurally. From the premise, one can predict many of the things that will happen. But these authors are so good that it doesn't matter. It feels fresh and unique and surprising the whole way through.
I recommend starting with Hot Head. This is a book to be studied by aspiring romance writers. It is obviously great at the level of subtext: dialogue and action says more than what is on the surface.
But where the book really shines for me is in how, in writer's terminology, it "progressively complicates." This is the technique of gradually raising the stakes and putting the characters through more and more extreme difficulties.
If someone tells you where a book starts and where it ends, you'd say, "No way!" But a master of this technique can make each escalation small enough to be believable. It's great! I've since gone on to read everything Damon Suede has written. He's definitely a master.
I recommend starting with Valor on the Move, though she has hit pretty much every sub-sub-genre one could ever want, so take your pick. I think her main strength is in the interaction of character and circumstance.
She's so good at creating that perfect tension that comes from an impossible situation. It could be that the characters fall in love, but it's forbidden.
It could be a subtler character flaw or personality causing the tension/conflict. No matter what it is, the story drives right to the end with so much uncertainty.
N. R. Walker:
I recommend starting with The Weight of it All. Though, I plowed through so many the first few months of discovering her, and they're all great.
To me, N. R. Walker is the master of tone. She can create serious characters and goofballs alike, and the prose tone stays consistent to demonstrate the inner workings of the character.
This makes the romance and attraction feel all the more real. I'm not sure I've ever read one of her books without some level of swooning on my part.
Like I said, these aren't the only ones. I think T.J. Klune is basically single-handedly changing the face of MM Romance in the best possible way. But the wide variety of what he does isn't really strict "romance" like I was going for in this list.