When Rattlechains was spoiled, I thought that given proper support the card looked excellent. As things turned out, spirits weren't well supported in Shadows Over Innistrad, and there was no obvious home for the card. In Minneapolis Saito went 12-3 with a deck happily featuring the full four copies, and last weekend in Atlanta Hugo Terra made the Top 8 of the Open with this list:
While this deck has some ability to utilized the enter the battlefield ability on Rattlechains, the idea is mostly that cheap fliers are just good right now. In particular, having early evasive pressure for Nissa, Voice of Zendikar can matter a ton against tokens, and flash threats are great against sweepers like Languish.
The exposure that Rattlechains has gotten recently has caused the card to jump from bulk to about half a ticket on MTGO, and I have feeling that we'll be seeing more Rattlechains in the future. In particular, if spirits are supported in Eldritch Moon, Rattlechains could stop being merely a card taking advantage of the metagame and could be part of a deck that is more abstractly powerful. Paper copies of the card are currently about half a buck, and this could easily be a $5 card at some point in its Standard legality.