I like Nurarihyon no Mago. It's definitely less "mature" than many other manga running in Jump, but it's still pretty entertaining, and it doesn't seem to have fallen prey to shounen-cliches yet. There isn't fighting action in every small story arc, for instance, which can be a relief; sometimes, it just isn't necessary. I wonder if it'll eventually go down the plot path of having one strong villain, though...
I've heard good things about Double Arts but haven't read it; Bari Haken doesn't seem to be too popular as it hasn't been scanlated past chapter 2.
Double Arts starts off with the narrator telling about a plague that's infected much of the populace, and only special people called "Sisters" can temporarily halt the spread of the disease in a person. One day, one of these Sisters succumbs to the disease, only to have Main Protagonist Dude step in and save her. Turns out, MPD is immune to the disease, but the Sister can only live if the two hold hands...24/7.
That's basically all that's happened thus far. The Sisters are trying to get MPD back to HQ so they can study him, but there are bad guys trying to stop them, etc.
I just read Double Arts, it was promising at the beginning, but then it turned pretty average.
There's a new Masshima Hiro (Fairy Tail, RAVE) in Kodansha's Shonen Rival, Monster Hunter Orage
If you like his style, it's worth a read... but the similarity to Fairy Tail is too high...
Other interesting publishers? Just stumbled over Mag Garden. I really don't know all the publishers and the magazines. There are ton's of never scanned series o_O