Hello, I could firstly say without a doubt, Quad-core i7 are far better as they have 8 threads ( compared to 4 threads on the dual-core ) as well as larger L3 cache. However, in terms of battery life and price, dual-core will take the lead. Normally, MQ, HQ, are referring to the quad-core's and U and M is representing the dual core version. Normally, Quad Core i7 will have a starting price of 600$ as they are normally paired with dedicated class graphic processors.