There's absolutely no comparison between the Nexus 7 and the Kindle Fire. The Kindle fire is worse in every single imaginable point. The Kindle fire also isn't a challenge for Apple at all. If anything, the Kindle fire has helped Apple due to people being disappointed in how bad it is and so they get an iPad. Spec for spec, the Nexus 7 gives the iPad a run for its money while being significantly cheaper. Shame they didn't come out with a 10'' version or I'd consider it.
That said, The Asus Transformer line is still what I'm eyeing. The TF700 is supposed to be released some time this month, and I'll probably snag it some time in the fall or winter.
The issue still remains, no one can make a tablet as user friendly, large, and usable as the iPad.
Sure, the Kindle Fire may be giving the iPad a run for it's money, but it's definitely not user friendly, and way too small to be a usable tablet.
However, I do not know much about the Nexus 7. I'm guessing that's it's got great features (Adobe Flash, anyone?) but it's still not large enough to compete with an iPad. The iPad in itself is famous for being an iPad, but it's 10 inch display really sells people. 7 inch tablets like the Kindle Fire or Nexus 7 can't really compete with the iPad. People want big tablets, that's what a tablet is for!
It seems to me that the only tablet that truly gives the iPad a run for it's money is the Le Pan II. It covers pretty much all the bases against the iPad, I'm not really sure why it's not a huge thing.
Did you know that iOS apps crash more frequently than Android apps? Apple just freezes the device or makes it look like you never launched it rather than admit there's a problem (which would allow the end-user to look for a solution online). If that's what makes something user-friendly, I want no part of it.
The iPad is actually 9.7 inches, and a horrible 4:3 resolution. It's not 10 inches nor is it wide screen, so watching videos on it is lacking. I want no part of that either. As for devices that compete with it: Asus's line of tablets have been amazing. Got my mother the original transformer and looking to get the TF700 for myself.
I dunno why you even brought the le pan into the picture: horrible hardware and brought the worst aspects of the iPad into the Android tablet market. It's the posterchild of cheap iPad knockoffs.