depends on the GPU series. but to my knowledge, if use GPU better to mine on ETH, ETC, Zec because of those coins which I feel profitable. 4 months ago, I once mine ETN used 2U 12 cores 24 threads and get 30 ETN per day. but for now, it is not profitable.
Yes i think same here with GPU mining. Maybe electroneum mining is not that good choice to mine with gpu;s. I rather have to take a look at ETH or ETC.
because ETH and ETC has a great future I do believe.