The 600D doesn’t have intermediate ISOs, Kelvin or quite as fast of a High-Speed Continuous shooting mode as the 60D, but otherwise is pretty similar (and you can close the gap on some of the features with Magic Lantern).
The 70D is a good upgrade over the 60D, so I don’t know what kind of prices you are seeing in your area, but if it’s not much more, I would consider that as well.