Anisotropic has been a bit of a frustration for us because while it is very easy to do (it's really just a flag to DirectX), the compatibility issue I mentioned before made it a pain to actually get it in to the control. It's a shame we couldn't turn it on by default, but at least it's there. The effect of it is really quite dramatic, as you can see below. I took these images at this location, near the 405 and 90 interchange in Bellevue.
With anisotropic filtering enabled:
To turn it on in the website, click "options" in the upper right corner, then "3D settings", and finally check "Use anisotropic filtering". To turn it on in code:
These settings are remembered in the user.config file for future runs of the control. The perf penalty for this on cards that are even remotely modern is almost zero, so go turn it on now!