I’ve been working on UE4 for the majority of my time at Epic, and I can finally talk publically about all the cool stuff that went into it! We announced (and launched) a subscription plan last week at GDC 2014.
You can get access to the UE4 editor, tools, and entire source code for a $19 per month subscription (and 5% gross royalty if you make money off of it). We’ve also got a bunch of code and content examples, with more coming over time. The EULA and subscription terms are concise and reasonable; you can cancel at any time and keep using what you’ve downloaded, renew when you want, etc…
On a related note: I will also be blogging at unrealengine.com, starting today with a post on Blueprint Editor Tips and Tricks, including a printable cheat sheet of BP editor controls / shortcuts (Cheat Sheet or Printable version).