So, updating as of March 2020 - I am now following Snow Man.
Over the years I have followed closely various groups. My first Johnny's group, and the one that I always follow, even if I have my attention on another group at the time, is ARASHI. I don't think them being the constant in my Johnny's following will ever change.
After that, the groups I followed relatively closely were first Hey Say Jump! and then Sexy Zone.
But now Snow Man has definitely caught my attention. They're a newly debuted group that has 9 members, many of which have been a part of Johnny's Junior for years and years and years. They're such hard workers, have really good teamwork, and bring a sense of professionalism and maturity which I really admire for a newly debuted group. That probably has a lot to do with the older members, especially considering you have members that are 27 that are also mentoring the youngest, Raul, a 17yr old.
Anyways, Iwamoto Hikaru is my fav, but Meguro Ren is also someone that naturally catches your attention.
It's surprising that I follow Snow Man considering ~2yrs ago I was really into SixTONES. But, like I mentioned, the team dynamic with Snow Man that I started noticing on their YouTube videos made me become a fan of them so easily.
If you haven't checked them out, please do. Their live performances are amazing, dare say some of the best in years. Their choreography is also very modern and fresh and not the cliché Johnny's choreo we used to see. This is in part due to Iwamoto choreographing quite a lot. Check out Crazy F-R-E-S-H Beat which was choreographed by him and at the moment has 12 million views.
https://youtu.be/lfVfBqkk2Vo Also, definitely check out their videos on the Johnny's Junior YouTube channel. A decent amount is subbed, and you'll definitely understand why they're so loved.