Get a NEX. They are the greatest. Two slots: one for Famicom carts and one for NES carts. Plus you can use any NES-compatible controller. Plus they have wireless capability BUILT IN. Plus they never blink. There are like 3 or 4 games that won't work with it, but when you're talking about an overall library of thousands of games, what's 3 or 4? Plus, the power supply is the size of my thumb.
The one downfall, if it can be considered as such, is that certain colors in the pallete are slightly different shades than the original NES. Not all colors mind you, but a few. If your TV is like mine it will have a number of configurable presets for different contrast/color set-ups. I adjusted one of the presets (by adjusting Hue/Tint and all that) so that the NEX, when played with that preset, looks the same on screen as my real NES. You would never know the difference! Even without that ability, the color thing is pretty minor. A casual gamer would never even notice.