While The Guru 5 primarily looks at the actions and thoughts of--you guessed it--only five of the best investors, GuruFocus is a good site with a much larger scope.
They have some useful data on portfolio positions, show how much money of an invested portfolio is in a given industry, and a decent news feed. They also just added portfolio performance charts, which allow you to see what Warren Buffett or Ken Heebner or Bill Miller has done for investors lately. (For a good example, showing Berkshire's performance relative to the market, click here.)
One of the things that GuruFocus does well is show the activity of a lot of different managers with regards to a single stock (over a set amount of time). And, on the same screen, it will show whether insiders were selling or buying, or both, and in what numbers. This is good stuff--great stuff actually. So, if you have a single stock you're interested in, this is one of the best places to get a broad view of what others are thinking and doing with regards to it.
However, the growing lack of focus at the site can be as much a vice as it is a virtue. It really depends on what you are looking for, and how much time you have. I noted above that the news feed was just "decent" above, for example, because I really don't care about many of the articles linked to (written on lesser investors) and I definitely don't care to read some of the articles posted there (written by lesser investors).
The same that can be said about the news and articles feed, can be said about the site's forum. Some good discussions can be found there and a bunch of worthless one's as well (relative to what could be read elsewhere). I don't have the time to wade through the bad, or argue with it, in order to reach the good.
And, while I don't think it's necessarily wrong to do that, given other options I would not recommend it--especially for new investors. Far better to read everything the greats wrote, or good books on them, then start reading the letters of lesser investors, and so on down the chain.
GuruFocus is a great site, but because of the volume of managers and information, one should clearly define one's purpose in going to it, rather than mindlessly click around. If you do this latter, you will likely waste a lot of time and not learn a tenth as much as if you read a book or a handful of shareholder letters.
If, however, you use the site for getting a quick view of what managers are doing in general or with regards to a specific company you're focusing on, I think you'll find it very valuable. From there, you can judge for yourself the value of each passing news item or article.
Note: the site's forum contains a steady stream of articles cut and pasted from other writers or sites. That's a copyright infringement issue for the owners of that data or of the site itself to end, but I mention it here simply to say I was not referring to it above--when mentioning the good parts of the forum.