1200D (T5) or 100D (SL1)

SL1 vs 1200D. 
-Both have the exact same sensor and image but the 100D has more scattered Phase Detection AF points (works a bit better in lifeview focusing)
-Both have the same size screen, but the SL1 has higher resolution and is touch opertable.
-The bodies otherwise are absolutely identical. Both are comfortable in my hand but for comfort I'd give the 1200D the win. Just for the bigger grip and more buttons while the 100D is mostly touch opertable. Which both are fine for different users. SL1 has 8 buttons 1200D has about 14
I prefer the 1200D size and buttons.
- 100D is faster 1fps (4 vs 3) 
-100D Has a microphonre input for audio (huge one for videographers) 
-100D is almost a 80gm lighter
-100D has a smaller shorter rated battery. 
-100D has 18-55mm STM in general while the 1200D generally comes with older lens. 
So yes if they were housed in the exact same body for the exact same price

the 100D would be a better choice without thinking twice.

But it's not. It has different body,

very different. So look into how it will fit into your hand and how you'll like it.

I wanted the SL2 features in a 1200D like body (which I much prefer for the grip and buttons and went the 700D/t5i)

14 buttons vs 8 buttons. And VERY annoyingly is having to use left hand to press menu. This is an issue even in my 700D but the 1100D and 1200D surprisngly have the info/menu on the right, making the camera MUCH fater to use and your second have does nothing aside from zooming or focusing. 60D and 70D are 1100D-series like in grip oriented buttons.

The grip is pratically non existent to make a secure interlock with a larger lens. My 55-250mm (which is still not that heavy) is very awkward on the SL2 while very natural on the 1200D and 700D.  The shutter button on the 1200D and 700D falls naturally at the extend of your thumb, while the shutter button on the SL1 I found I had to physically mode my finger back to click, like Nikon camera. Just some very minor information for those who need it.

So aside from me or you specifically needing a more comfortable body to use, get the SL1. 
The Sl1 size is great. Almost a mirrorless. This thing plus a 50mm is a wonder for go outs and parties. But also any rebel line + 50mm is still small too. Just a great combo.

either cameras can't take world class images and you're only limited but your imagination. So shoot and shoot. Get Canon STM lenses to help get more creative shots and glass, this is extremely unique in Canon vs the other companies. They have a line up for their APS-C glass that costs almost nothing yet is one of the sharpest and highest built. I've done a side by side with a 55-250 STM VS a 70-200mm f2.8 II IS both at 200mm f5.6, the STM had a better IS and got identical sharpness. Whoho.

These lenses are (from wide to tele) 
1- Canon 10-18mm IS STM

2- Canon 18-55mm IS STM

3- Canon 55-250mm IS STM

4- Canon 18-135mm IS STM (kind of replaces 2 and 3 if changing lenses isn't your thing)

5- Canon 50mm f/1.8 STM