I like the original Strike Force model. The sparkie is too fragile for my tastes. Plus the strike force has a spot to store tinder as well.
A standard 3/8 - 1/2" ferro rod without a striker or anything would be my first choice though.
The sparkie is nice being so small and easy to strike, so I think it might be good as an out of the way back up or the like. If the part that holds the ferro rod in place were metal or a better composite material it would rate much higher, but it's just cheap plastic which breaks easily.
Eventhough that sparkie broke it still can be used, but must be first pryed out with a knife.