For me it has to be Naoki Urasawa. I think both Monster and Death Note are amazing, and I actually think DN is a tad bit better, however Urasawa has other manga, that are better than Platinum End, and high level consistency and amazing delivery.
Monster is a masterpiece. Johan is legitimately one of the best characters ever created.
Obata and Ohba are in 2nd place, probably tied with Miura.
The rest are interchangeable imo to some degree, with probably Gege being at the top followed by Fujimoto.
I haven't read any of the works of Inoue and Togashi tho.