Read my guide for Canon cameras here. DxOMark tested the Canon EOS Rebel T6i and T6s DSLRs and found their sensor score practically identical. Below is an excerpt of their findings :
Rebel T6i (EOS-750D)
'As an entry-level model the Canon EOS 750D (T6i) makes some compromises in layout and controls — for example, there’s no top plate LCD as found on the EOS 760D(T6s), but sensor performance is on par with the camera maker’s mid- and high-end models, the EOS 70D and the recently-introduced EOS 7D Mk II. While it’s true that the Canon sensors are behind the very best APS-C models in terms of low ISO performance (particularly noticeable when comparing dynamic range), the company is making some noteworthy advances.'
Rebel T6s (EOS-760D)
'While it’s not our place to discuss why Canon should choose to introduce two models that vary mostly by their controls (although the 760D’s tracking AF capability in live view is likely a worthwhile feature), the sensor performance for the EOS 760D is intriguing. Canon has made significant advances over the previous generation sensor, particularly with regard to low ISO noise levels and improved dynamic range. While sensor performance is still behind the very best APS-C models, Canon appears to be taking up the challenge set by Sony, and while it’s still got some way to go, that has to be good news for the consumer.'