Was going to list some plus and minus points here but I reckon op isn't coming back.
Please list them. I am also toying with the idea of getting a SLR. I like the price of the D3300 but would like all the feedback I can get. I know ultimately I will make my final decision based on what feels best in my hands and has a good button layout. But always like having the pros help narrow things down.
Nikon uses a newer better sensor than canon uses. This is the big buzz point for all nikon/pentax/sony users, as they use a sony designed sensor that beats the canon sensor in dynamic range and maybe a little in noise reduction (a few models use a toshiba sensor, also highly regarded).
However this is the main reason that nikon get recommended over canon camera, and while it is a good reason, it does not take the overall picture into consideration (pardon the pun). A lot of users will never see any discernable difference between photos taken with an entry level canon or nikon. It is often said that the real contributing factor after the user ability, is the lens.
Look at these links below, one is from a 1200d, the other the d3300
Canon 1200D : Specifications and Opinions [JuzaPhoto]
Nikon D3300 : Specifications and Opinions [JuzaPhoto]
Now tell me the 1200d cannot take good photos and the d3300 sensor is way way better. as you can see, they are both very very capable
Usability wise both cameras are very similar. I used canon for a while, now I use nikon. I prefer the latter but canon also has a few tricks up its sleeve, especially if you like live view stills and video, with more control in canon cameras allowing aperture control without having to go out of live view and back in.
Also any canon I have used supports high speed sync flash with a compatable flash, a feature only on the higher levels of nikon cameras (don't take my word 100% for this one with the 1200d, but I am fairly sure it does also)
Another feature canon has which I liked, is when shooting macro using an af lens, when you turn the focus to manual you can set the camera to beep when a chosen focus point is in focus point is in focus (the af function is not controlling the lens, but the camera is telling you the selected point is in focus). It is great as an aid, nikons version has a green flashing light in viewfinder, but its hard to concentrate on this while trying to manually focus.
All in all if it was a choice for me as a beginner to get a d3300 with a 18-55 or a 1200d with an 18-55, I would pick nikon. But when the price of both is similar, and canon is a twin kit lens i would definetely go with the twin kit. For many, this is as much gear as they would ever need.
Of course everyones needs and opinions differ