The reason they jump around, of course, is that they attempt to find the "best" position for any given view of the map.

"Best" is defined as:
- entirely visible (not clipped at screen edge)
- not obscured by other map objects
- on a reasonably straight part of the road

If they were made "stable" instead of adaptive then we'd have some other problems:
- roads not labeled at all in a given view
- labels clipped at the screen edge
- labels obscured by eg. a POI popup box

Since we'll be printing the map, the above problems are pretty serious.

Possible remedies:
- Draw the same label many times, hoping that at least one is visible.  This is what Google Maps does, out of necessity.  It adds a lot of clutter.
- Reduce the negative aspects of "jumping labels", perhaps by having them fade in and out smoothly.  (Must they fade out?  Maybe just wait until they're off screen and then remove them?)

My vote is for keeping the adaptive behavior and maybe some day adding the fading.