I'm in a great confusion on which one to get. iMac 27-inch 2.93GHz Intel Quad-Core i7 is priced $1569 - Refurbished. I was looking to get the i5 iMac @ $1699, which has the thunderbolt. Apart from processor it has 1GB Ram and compared to the 2011 model just has 512MB Ram. Which one you think best worth for the money?