Trends change but right now i'd say "trap rap" (ex. Gucci Mane, Future, Young Thug, Migos, Rich Homie Quan, Fetty Wap, Chief Keef) is one of the subgenres with the fastest growing popularity.
I think its the next generation of the golden age of gangsta rap (NWA, Jay-Z, Wu-Tang, 2Pac and B.I.G.).
I listened to alot of early gangsta rap in my teens and moved to listening to alot of old school later on. I was big into lyrical hip hop, conscious hip hop and even storytelling hip hop.
Today's artists of this new genre of "trap gangsta rap" are definitively not aiming for great vocabulary or intelligent rhymes. I think most of today's "hot" rappers grew up listening to old school and know that they won't do it better than the legends in that category. Fans are looking for the next new thing in rap. The real part golden age old school rappers couldnt master was flow. They had the lyrics but the flow was still at a very early stage.
Today the game;s standards have changed. The lyrics are now irrelevant, the flow is what these guys are after. The melody. How the words intertwine with the hi-hats and the bass. The melody. Such is why many of these rappers are basically singing on their tracks (Young Thug, Rich Homie Quan, Fetty Wap). Autotune is embraced if it can make the flow sound better. The mood has also changed. It used to be about hate, problems and alot of very depressing themes. Im glad today it is more "positive" talking about entrepreurship, boasting about success and repping for the squad. Even if many of the topics are still very negative (violence, drug use and misogyny), I feel the lyrics are "lighter", more positive and most of the time fuckin humorous. I don't want to hear anymore complaining rap. I would even go as far as to say a new subgenre of trap has emerged that i like to label as "motivational trap". The main actors of this movement are Young Dolph and Skippa da Flippa. Camouflaged in metaphors of braggadocious, misogynistic mumble rhymes are powerful messages of individualism, self-discipline, work-ethic, respect and entrepreneurship. Everyone has the opportunity to get up and get the money (or whatever ur chasing); no excuses.
These are good examples.
[VIDEO]https://youtu.be/Sw-IfoBHzqc[/VIDEO]
This is why i listen to trap.