Even in a case like this when both cameras use the same the lenses, it's a good idea to take the lenses into consideration because:
1) there are no 20X zoom lenses (like you have on the SX280).
2) there are no 10X zoom lenses that are good in low light.
So you should first determine which focal lengths you need and which of those need to be good in low light. Then subtract the cost of these lenses from your total budget. Then, if you have enough leftover for either camera body, you can decide whether you need an articulated LCD and/or 9 cross-type AF points, etc.
I have been thinking of upgrading from my current Canon Powershot sx280 hs to a beginner-mid range DSLR and have come to a difficult choice. Should I buy the Nikon D3300 or the Nikon D5200? Price, battery life, and size aren't an issue between the two. What I have found that is holding me back with my current camera is: low light capabilities, it's lack luster colours/contrast, and the overall sharpness of the image. I know and am comfortable with all the manual controls my current camera has, including: Manual Focus, Aperture, ISO, Shutter Speed, and White Balance.
TL;DR
I want a camera that will give me the chance to improve my skills and I won't get bored of. I don't care about price, battery life, or size between them.

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