Andrew Price, the author behind Blender guru, has been using Blender since 2004. He started Blender Guru in 2009, and now works with Blender3D as his day job as well.
His work/tutorials are very well know.
If you want to learn to solve very specific problems in specific ways, BlenderGuru's tutorials are great. If what you want is to know how to do certain things in general (make materials, sculpt, etc.), and make yourself a solid 3D hobbyist or professional, then you should look for a more generalized resource.
Not all of his techniques are physically accurate, even when he makes a point of the importance of physical accuracy. This is especially true with scale. 1 BU = 1m
They offer a great course for complete beginners that offer a variety of lessons and quizzes. It's a very easy to understand course that will give the user a solid foundation with Blender3D.
Some things need to be done for every single part and they show it every single time, which enables you to skip parts that are maybe not interesting for you.
CG Cookie was revamped a few years ago to better suit building a set of general, professional skills. The old content, which was more like the typical "how do I make a living room" or "how do I build a figure," is all available for free in the archive. It includes all their tutorials from 2008 to 2015, and they're some of the easiest to follow and most informative tutorials for Blender out there.
For the price of subscription, you access to all the courses on CG Cookie. That includes courses on Unity, game building, concept art, and physical sculpting. If your interest in Blender is part of a larger interest- making statues or figurines, making movies, building video games, etc., then CG Cookie is the site for you.
Blender Cookie has long become CG Cookie. The site includes whole courses of study that are divided along professional lines. For instance, texturing and game asset creation, rather than making plants or vehicles.
If you already have a very complete skillset and just want to fill in specific gaps of knowledge, CG Cookie isn't the best site for you. It's great if you want to add an entirely new skill to your repertoire, or learn a new tool or technique (they cover Zbrush, 3DS Max, and even lost wax casting). It's not so great if you want to get better at making clothing details, or improve your anatomy skills.
CG Cookie is great if you want to learn how to do something in general, like texture or model. It's now less good if what you want to learn is specific, like how to make really good grass or cars.
It's really for beginners or people who have no knowledge in the section covered. Also it's not in depth they only show you how to do one thing with each tool. For example you only use bezier curves, meta balls, and sculpting once in the entire course so you don't master anything just by following along.