I can't say too much for them as I have just signed up on March 10th, but I have been hearing about them for a while and I finally signed up.
After one day here is my earnings;
|71 Swagbucks so far|
I can cash in as little as 5 Swagbucks for donations or digital wallpaper, 40 points can get you discounts at several retailers. If you really want to save your Swagbucks, then for 75,999 points you can get a 40" Samsung TV.
Everything I have seen in my research shows that this is legitimate and I'm going to keep using them. You can either work off of their website or use a simple toolbar (Which I chose to do) The toolbar is easy to remove.
You earn earn by watching videos, weburfing and randomly finding codes. So far it's looking good, I will try to post an update in a month or so. In the meantime, click one of the links to sign up.