I fucking hate it. It used to be just mechs or just vehicles but now its just becoming more commonplace. Anime like Show by Rock that mix it or movies like Expelled from Paradise that just use it exclusively are just hard to watch for me. I think it looks bad and when superimposed on a 2D platform its just jarring to me. That being said I actually do like Sidonia no Kishi which is almost completely 3D because from the beginning it is part of the environment.
With the new Berserk anime coming I am just afraid of this trend changing from "Hand drawn anime with occasional CGI to CGI with occasional hand drawn animation."