I use tumblr for one on one rp. The format isn't the best but for one on one I find it pretty easy. There's a huge pool of rpers to chose from and everyone's posts are all right on their page so the crazy is usually pretty easy to spot, especially since most people over there don't feel the need to hide it. The rp culture is pretty easy to pick up on and I've found it really easy to avoid the sjw sections. Replies are usually faster too so when I just want to sit and boomerang there's usually someone on that I can with. This does come with the warning that you do have to wade through some drek to find the good writers and until you get the hang of it, it can be a bit awkward. The format is never going to be as user friendly as DW. I still prefer DW but given our speed slowing down here and the smaller writers pool I supplement with tumblr rp whenever I need a bit more.