I have used just about every ferro rod on the market and even have some custom models. I've heard they all come from Romania. That being said, I carry a BSA hotspark with me just about everywhere. On my knife sheath, I have the Army model firesteel. In cold weather, I use the Strike Force because of the larger pieces ease of use with gloved hands. These are my favorite production models. Marty Simon sold me some 3/8"x4" ferro rods that I had Greg Haugh of Lone Rider Custom Grips put handles on. They are some of my favorite overall.
While not a ferro rod, I do like the Spark-lite system the USAF uses in its kits and the tinderquick is just plain awesome. I'm not a fan of the blastmatch and have seen 2 or 3 break. The striker broke off on each one. If that striker falls off, it is difficult to strike it with just a nub of metal. For what its worth, it is possible to use a ferro rod with one hand if you step on it with your foot. In fact, this skill is practiced in reputable survival schools.
Just my .02 cents.