Actually Erich, they do seem to be a bit of a draw - the NEX-5N appears to have better overall noise performance, in that the noise pattern is very fine, uniform, mostly luminance, and not blotchy - the NEX7 noise becomes much more blotchy at the high ISOs, but the NEX7 has the greater MP and when resized can make up for much of that - in the end, most seem to agree they come out about even at ISO3200 - 16,000 (NEx7's limit)...and the NEX-5N actually allows shooting up to 25,600.
Red - as mentioned, the two extra control dials are a bit of a difference, and size itself is a bit different between the two, with the NEX7 being notably taller to accomodate the built-in EVF. ; There are also a few more user-customizable ranges in the NEX7, but otherwise not a huge difference. ; The NEX-5N allows for much more customization of controls than the NEX-5 did, so has surprising amount of external control without menu diving (up to 9 functions); the NEX7 with the two extra dials allows for more jog-wheel control over different controls than the 5N does.
It's totally up to you to decide...personally, I was more happy going with the 5N - the performance was exactly what I wanted, without needing to rely on post-processing to clean up and resize my photos for best results, and personally I found 24MP just overkill as 16MP is more than enough for significant cropping, publication standards, and large prints. ; I bought the add-on EVF to go with mine, which I love for shooting with longer lenses for wildlife and birds and such, but also like that I can take the EVF off and make the camera smaller when I want to.