They can generate sharp images if trained well, but they are notoriously difficult to train.
a lot of research efforts have been dedicated to the investigation into stabler training (Radford et al., 2015;Salimans et al., 2016;Nowozin et al., 2016;Metz et al., 2016;Poole et al., 2016;Arjovsky and Bottou, 2017), and the recently proposed Wasserstein GAN ) is a promising technique along this line of research.