That's a hard thing to answer because everybody uses the N7's differently, peoples times will vary...

Exactly.  And everyone's usage can vary from cycle to cycle on their battery depending on how many videos are streamed, how bright the screen is, etc.

A counter to your counter .    With the Nexus7 you don't have to wait weeks for a custom ROM to get the latest version of Android and months for that matter to get a really stable version via CyanogenMod etc.   With the Nexus 7 your tablet is always up to date from day one as soon as the latest version gets pushed to your tablet.   No waiting or rooting needed for that full tablet experience.   Also, personally, I find the 'carousel' of the Kindle Fires to be stifling.   It's really just a catalog...it's not really a full blown OS.  It' more like having a grown up ipod that plays videos and shows books in addition to music than it is a real tablet OS.   There's no depth or flexibility to it.   Can't even put a wallpaper on the thing.

Totally agree, out of the box I love the N7 feel.  I think the kindle's ecosystem is more ios-like.  So better suited for beginners or folks who dont like to tinker.

This is a pretty close fight and will definitely benefit consumers.  Just some counter points...

The (free) map apps are lousy anyway.  I've had GPS turned off on my N7 for the past month.  Wifi based location will still work for things like weather.

I'm sure the new kindle will be rooted and have ROMs available as quickly as the old kindle and N7.  Users will only be locked into the ecosystem if they choose to stay there.  For those that aren't capable of figuring out root, a sandbox ecosystem is probably easier to handle anyway.

Jury's still out on which processor is better.  They're likely very comparable.  Dual core vs quad core doesn't necessarily mean its better. http://dottech.org/android/78943/nexus-7-vs-7-inch-kindle-fire-hd-which-is-the-better-7-inch-android-tablet/

That said, I'm still very happy with my N7.  Jelly Bean has been pretty awesome so far.

VPN or not, most of us grab up free apps like candy.  Those free apps could include key loggers and the like, especially if you are rooted.  Best just to avoid anything financial from mobile devices imho.

Does it have full functionality when away from wifi?
Is it fully open after purchase or are there in-app purchases?

To act on an email, tap on the 3 dots in the very bottom right of the screen.  That is the "menu" button and shows up in lots of apps.

For pictures, they open like any other attachment.  Once opened, they auto save to /sdcard and you can access them from a file explorer app or picture app.

I use firefox as my main n7 browser, mostly because it handles flash pretty well.

These seem like questions for the place where you downloaded Trinity.  I'd be very hesitant about playing around with kernel settings related to overclocking.