Dare one ask the question 7D vs 70D vs D7100: which has better image quality?
Worth considering because the D7100 is cheaper than the 70D.
That's a dangerous question to pose on this forum without starting a flame war, but I'll do my best!
If people were honest, they'd admit that the D7100 has the image quality advantage; it is superior on most metrics. The point of argument would be how much better it is and how important the image quality advantage is compared to other features. I would say that the D7100 is the better all round stills
camera, with its weakness being buffer depth, plus a bit of build quality compared to the 7D. That being said, one doesn't buy a camera body in isolation, but as part of a system. I wouldn't say that anything that Nikon has to offer is compelling enough to offset the changeover costs, if one has a decent collection of EF mount glass. If one doesn't own any glass from either manufacturer, then deciding which lenses one is likely to need is a factor. To be honest, unless you're into wildlife or sports, I'm not sure that either manufacturer has the most compelling lens line-up for their APS-C cameras and I might be tempted to look elsewhere (e.g. m4/3rds or Fuji).