Nice Fire Tin / Kit and something everyone should have...
If birch bark isn't available or tinder is scarce i always go to my Mag Block - I am a fan of the magnesium blocks - they are definately a winner, although i believe the rod imbedded within them is actually flint based and different to ferrocirium and so producing a slightly cooler spark.
The biggest problem i find with these magnesium blocks is that the striker always seems to wear away - way before the magnesium is used up...
I am always on the look out for one with a BIGGER striker...