NFSN is a virtual hosting service, which means that small sites don't pay for capacity they aren't using, and large sites are automatically load-balanced. NFSN-hosted sites regularly get links from Slashdot, Digg, etc. and they stay up.
Pricing: NFSN is pay-as-you-go: bandwidth starts at $1/GB and goes down based on your usage, and storage is $0.01/MB/month. I'm paying less than $7/month for my site, and most of that only because I'm running a web app that's a derivative of Wikipedia. No stupid pricing tiers here.
Environment setup: you can set up your shell for public-key access over SSH. Their environment comes with Emacs 22 and git installed, which means that, for once, my web host shell is actually useful and not just a pale shadow of a real working environment. (Yes, vim 7.1, bzr, hg, SVN, and CVS are installed too.)
Abuse policy: here is a clip from their abuse FAQ:
A NearlyFreeSpeech.NET member site is defaming me or otherwise injuring me civilly.
Please forward a copy of your legal finding from a court of competent jurisdiction to our contact address. If you have not yet obtained such a finding, a preliminary injunction or court order is also sufficient.
The rest of it reads similarly. It is nice that there are web hosts out there that respect their customers, even when those customers don't have absurdly priced SLAs.