It does depend on the game and yes always research before you buy, regardless of early access or not. But come on, you really don't know what they're going to do. I've played The Forest, and if you bought Early Access you have no guarantee anything stays the same. Maybe the devs decide late that a plane crash is too much like Lost and go for cruise ship crashing and you and the child finding the island in a sinking lifeboat. Maybe they think the natives are kind of insensitive to some societies and make them more naturally peaceful. You really just don't know what goes on in those meetings, no consumer does.

I still agree, research is important. But look at DayZ. At the time of the launch it seemed stupid not to buy in. It's a for sure deal, right? Teamed up with Bohemia Interactive, wow it's not just a mod anymore it's the real deal! Not only a team, but teams working on it! Play as they build along!

There simply is not upside to buying early access other than playing other than playing early on a build devs say will be rough. It's in the "What is Early Access?" statement. You're buying an unfinished product that can rapidly change any time. For a while no one got upset at it, I'm happy people are skeptical now. You should be too.