Those who have played Skylanders: Spyro's Adventure, could see this coming from a mile away. Activision releases limited edition "legendary" characters exclusive to Toys R Us. In addition to this 3 pack, a Legendary Bouncer giant has also been released.
Be aware that legendary Skylanders are more like collector's items, because of their exclusivity. If you intend to play with them, I suggest you keep the figures in the box and put the whole box on the portal (it can be done, even when using the online Spyro's Universe), because when the Toys R Us stock runs out, the legendary figures skyrocket in value.
If you're new to Skylanders, I suggest you play with a few of the characters to see which ones you're most comfortable with. The legendary characters are just like the regular versions except with slightly better stats (more luck and attack power) and that blue/black and gold colour scheme. Their abilities are no different from the standard versions of these characters.
I'd only recommend forking out for legendary Skylanders if you seriously want to "buy 'em all" and ONLY from Toys R Us, don't feed the scalpers around here.