I bought myself a Nexus 7 for a combined birthday/Xmas present to myself, and I love it. My prior tablet was a Nook Color, and except for one thing, the Nexus beats it hands down.
The processor is SO FAST - there's a reason it's generally considered the best 7" tablet on the market at the moment.
The one thing it didn't beat the NC on was the screen - the screen is nice, but the NC was Technicolor eye-popping. Really saturated colors that made me go, 'Wow!' every time I played a video on it.
The absence of an SD card slot doesn't really affect the comparison for me, as I was using the SD card slot to run a custom ROM so it was only marginally useful for other purposes. A tablet is not my preferred video watching device anyway, although it's nice to have as an alternative.
One thing I do LOVE about the Nexus 7 is the ergonomics for reading. I can hold it comfortably in one hand and use the volume button to turn the page, which is my preferred method. One-handed reading beats two-handed reading any day, and the N7 is the most comfortable device I've used since my old, old, old Franklin Ebookman.
It all comes down to what you need - I think the N7 gives the most bang for the buck, which is why I bought it in the first place, but it's also very comfortable and very easy to use.