I haven't run gNewSense, but I did run Trisquel for about a month last year on a box. I couldn't see much difference between that and running Debian without non-free repos.
I don't really care about trademarks - I think that is a giant red herring, and in fact I think it gets people into trouble running non-secure versions of Ice Weasel without proper security updates. I'd much prefer anyone in my office running straight Firefox, and in fact in the past I've forbidden the use of the older versions of Ice Weasel from the Debian stable repos.
I may sound like a newb on this issue, but I'm not - I just don't see the difference when I avoid proprietary software by running plain Debian. I know you can implement binary blobs in the kernel if you want on Debian, but you certainly don't have to, anymore than you have to use non-free repos. Am I missing something, or is this just the "militant FSF crowd" going a bit overboard?