Well, right now there's a pretty good deal on the T6i + 18-135 IS HTM lens at Adorama. There's a $150 instant rebate, plus Adorama throw in a bunck of extras like, filters, a useful camera bag, a bunch of software and on to pof that you get $18.98 back in store credits -
http://www.adorama.com/ICAT6IK2A.html?kbid=12417There's pretty much the same deal on a T6s package -
http://www.adorama.com/ICAT6SKA.html?kbid=12417The price difference is $100, so what do you get with the T6s that makes it worth an extfa $100? Well you get a top deck LCD and a rear QCD (quick control dial). It can shoot HDR movies in real time, gives you a manual exposure option and digital zoom in movie mode plus the ability to connect an external microphone. The T6s allso gives you Servo AF in live view mode so you get continuous AF when shorting burst of images. The T6s also has a single axis horizontal electronic level and has an eye sensor to switch of the rear LCD when you use the viewfinder.
Otherwise the cameras are identical, so if the extras of the "S" model over the "I" don't give you anything you want, then get the "I". Personally I think it's worth the extra just for the top deck LCD and rear QCD, which makes it hadle much more like a 70D series body than a Rebel.
HOWEVER - If you're thinking of spending the extra $100 on the T6s, Adorama have an "open box" deal on the EOS 70D with the 18-135 lens for the same price ($1089) -
http://www.adorama.com/ICA70DK1OB.html?kbid=12417 Open box items carry the full Canon warranty and some with all the accessories. manuals, software etc., but may have been store display items or may have been returned (unused) for some reason. Except for the box (which may or may not be perfect) they should be otherwise perfect. The 70D has fewer pixles, but a faster shutter (1/8000 vs 1/4000), a larger (and brighter) viewfinder, a pentaprism rather than a pentamirror and a battery that lasts twice as long. It also has a faster flash sync speed and a faster continuous frame rate. The 70D also has slightly better AF when using Live view.
If you don't like the idea of "open box", the 70D + 18-135 you can get it for the same price, with a Canon PIXMA PRO-100 printer included, but you have to send in a mail-in rebate for $350. If you don't want the printer you can sell it! Your final lost is the $1049, less whatever you get for the printer (at least $100).
http://www.adorama.com/ICA70DK1Z.html?kbid=12417Something to think about?