IMHO the 7in market is still not that good. The ipad is too much of a compromise with it's low res display, and slightly older hardware(they should have given it the A5x). Holding it also seems to be a bit of a hit or miss.
The Nexus 7 is build is questionable, with a screen res that is acceptable, but color, nits, and contrast could be better. The app store is also lacking tablet apps. Price is right though, but that's not surprising since is using the dated Tegra 3.
Kindle is screen is better, but again your stuck with Amazon's customization, ads, and app store, which is only really worth it for the free app of the day. Sure you can root it, but that still doesn't fully solve the lack of apps. Again cpu could be a bit better.
The only real 7in tablet that sort of had me interested was the HTC Flyer/Evo View, as it had a digitizer(though it's N-Trig and not the better wacom, but still better than nothing). The key faults were the lower res display, single core cpu, and no pen silo.
My perfect tablet would actually be either the Flyer with updates specs(i.e. S4 Pro cpu), full size sd(vs micro on the current), and retina display. Or an updated iPad Mini with the iPad 4 internals, and a wacom digitizer.