Valve's Steam service has updated its FAQ, and is now warning customers about buying early access games. Valve's official stance is that gamers should only buy the game if they're excited about playing it in its current state, in part because some developers may not ever actually release the game:
"It's up to the developer to determine when they are ready to 'release' - Some developers have a concrete deadline in mind, while others will get a better sense as the development of the game progresses. You should be aware that some teams will be unable to 'finish' their game. So you should only buy an Early Access game if you are excited about playing it in its current state"
This is likely due to the fact that there have been a large amount of complaints from customers. The early access system has come under fire from some, as developers have been known to abuse it, but we've also seen games such as DayZ really benefit from the scheme.