Small yet

The EOS 100D has really everything you of an SLR expected (unless you're comparing autofocus and continuous shooting rate with a 1-digit EOS), moreover, it is so light and small that you takes them simply more / better (eg in compared with a 7D with battery grip, external flash and heavy telephoto - it certainly all depends on what you want to photograph), especially with the 2.8 / 40mm Pancake. About T2 adapter you can also use fast times at the telescope without having to worry about the focuser (because then, if necessary, but missing the folding screen), it weighs just over 400g yes.
Image quality and noise performance are quite good, considering that 18MP are housed on an APS-C sensor. The positioning by Canon as a "beginner" camera I think is understated, rather it is a "secondary housing" for those who do not always want your Mark III or whatever lug. (Of course, it is also suitable for beginners, the main thing, the wheel is not on the green rectangle ... ;-))

Of course, the "little one" plays with larger lenses a good figure (eg, Tamron 70-300 VC, etc.), but since you have to first get used to it a bit. Instead of the included strap it can be worn wrist strap very well over long distances with a (stable DSLR).

Tip: If the 18-55 IS STM has not yet, should be equal to the kit purchase with this - it's easy and sharp (and relatively well-made for a plastic part) if the slow aperture ratio and the WW-distortion a not disturbing.
By the way: The 100D has the mechanical sensor cleaning ("dust-shaker"), the new 1200D, however not!

A non-negligible advantage is (as with all my known EOS cams) of sitting in a small hollow-timer (ergonomics / handling / haptic), with the competition (N., S., P.) always sits this fact on a horrible little "Huckel" - the on / off switch. When he is on the other hand 100D where it belongs, with the Mode Dial. (Ok, admittedly, in the older 2-digit switch was also placed inconvenient, but at least not under the trigger.) Go times in a photo shop and take cameras from different manufacturers in the hand: It really makes a difference!

Conclusion for the 100D is however: Beautiful camera, highly recommended.