What's the photographic ability of Canon 700?

Surprised me. First of all, there is something wrong with your description. D600 and D700 are Nikon's mid-to high-end full-frame cameras, and their performance is definitely very powerful. Canon 600D and 700d are entry-level cameras of Canon.

The main difference between the two is that the focusing system is upgraded, and then it is obvious that the 700D supports touch screen operation. I hesitate, the coms imaging components of the two cameras are exactly the same, and the picture quality is exactly the same. If you don't consider the price, of course, buy new ones instead of old ones. 700D has a touch screen, which is convenient. However, considering the cost performance, the 600D is still worth using. As a SLR, I think the significance of touch screen is extremely limited. 18- 135' s 600D (that is, the big set) is less than 5000, so I have practiced enough. I have a friend who bought it this way.