All three similar projects are in almost same situation and level of development with slight difference. There is also space in room to absorb all three to have proportionally share in the market. After releasing of any of these others will surely use experience and situation of that to advance in delivering. Golem is pretty much interesting and still in the game to deliver.
The good thing as a new investor is that the price is down for all the three projects and it is a good time to get into any of the three or invest an equal amount in all the three.Whoever is going to launch their first working version will be the one who would be leading this market from the front.