I gave the 50/fifty on PS a shot recently and still play them from time to time. After around 600 games I am almost dead on break even overall but oddly enough with way better results in 7$ games than 3,5$ games. In the latter I am actually cashing in less than 50% and therefore losing with a 9% negative ROI. Since these games are so fast, 600 is still not a huge sample. But it has been enough for me to conclude, that this is probably not a format, where I am ever going to make significant money.