some games are amd optimized and some are nvidia .. so i think u shoudn't really make a choice depending on special features.. nvidia's got physxx and amd are preparing with their mantle(which is already out and gonna improve day by day) ..
u just consider the performance.. and looking from that angle i would recommend a gtx 760 obviously over a toxic edition.. cause a toxic edition is already too overclocked that it won't let you to push it much further ...
i would say get a vapor-x or dual-x for a little less like 30$... which is a big amount compared to 14$ and u could easily overclock it to get the stock performance of a toxic edition r9 270x..