It really depends on what you are intending to use it for. Its more realistic to compare the new Nexus 7 against an iPad mini since both are circa 7" albeit on different OS and apps availability.

An RT however, is more practically positioned as a middle ground between tablets and ultrabooks. It comes loaded with MS Office and with its very decent batt life of 8 hours, very ideal for students and even work. If gaming is top on your list, strike the RT out. Just my 2 sen opinion