Because GNT is far above its ICO value and SONM is slightly below its ICO price? They're similar projects and if they perform in similar ways SONM will be shooting up in the next few months, much more than GNT should. They're also both in alpha, even though SONM started much later. And SONM has a much broader vision than Golem does. Either way, do your own research and make up your own mind or you will get burnt at some point.