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The sensor is pretty much the same on all of those, so you should choose based on how you like it. The t4i and 60d have better AF than the t3i, but all will take essentially identical pictures. The 60d has better ergonomics, better battery life, and a brighter viewfinder. Another (and cheaper) option is a used 40d, which would share batteries with your 5Dc.
The 60D also has a much larger RAW memory buffer than the Rebels: 16 RAW files vs 6 RAW for the T4i.