Here is a round-up of hands-on reviews and previews of the brand new Canon RF…
[Review] Rebel T4i/650D/X6i Studio Test Shots
imaging-resource published test shots made with a production Rebel T4i/650D/X6i. The whole ISO range is covered (up to 25.600), RAW files are also available, all samples can be downloaded in original resolution. These are studio test shots, i.e. test shots made in a laboratory setting. Btw, it seems that Canon was really fast to make the Rebel T4i/650D/X6i available: most shops are reporting that they have the camera in stock and ready to ship.
Rebel T4i/650D/X6i price and availability check: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA