I have a Silva Field and the Silva Ranger S. I am satified with both. I carry them in a pocket (one at a time).
If you can afford it a compass with a global needle would be good. It makes use easier as it allows more room for error when leveling it.
It would be a good idea to actually use the compass prior to the survival situation. The Silva Field is cheap enough to own more than one. SO one can dwell in the kit and one can be carried for pratice.