are they accurate enough to import into my 3d modeling software and draw a case around?

Love it

There's something weird on the right side. You can just see an indent in the right edge. Very easy to see on the first layer when you just start printing - the bottom layer doesn't cover the entire phone.

It seems to be with line 161:

translate([width - radius - height, radius, 0]) cube([radius * 2 - height, length - radius * 2, height]);

I've manually tweaked it to:

translate([width - radius - height + 1.3, radius, 0]) cube([radius * 2 - height, length - radius * 2, height]);

which seems to sorta put it in the right ballpark, at least in the preview. Would try and figure out what the real error is, but this thing takes so long to render in openscad..

I'm using openscad version 2015.02.20 (git 2cf9de3) on OSX, btw.

UPDATE:

This seems to do the trick:

translate([width - radius*2 + height/2, radius, 0]) cube([radius * 2 - height, length - radius * 2, height]);

fun to print this out and pass around the office... wish someone would do this for the sony z3 compact

The home button is wrong in the iphone 6 version (appears as a small hole vs actual home button), you can see this on thingiverse preview in your second photo. This is due to a function that you used in openscad that is only valid for versions later than 2014.03. I suspect you compiled your iPhone 6 and iPhone6+ models on different versions of OpenSCAD. I already fixed it and will try to upload the STL's and code