I was wondering if anyone had one of these yet, and if so, could you post your impressions? They look like they compare to the BSA Hot Spark, or at least are close in size. I haven't seen any in person but I was able to locate them online:

REI
Basegear

I recently purchased a "Light my Fire" mini fire steel. I have yet to have the opportunity to test it out extensively but it seems pretty solid. I seem to remember reading somewhere in a review that the striker (the shiny thing with the teeth on it) would be best replaced with a segment of a hacksaw blade. I think it would be a lot more effective that way...

I don't know how the Light My Fire model compares against the BSA model. I have a few BSA models (bought three - two to put in Altoids PSKs and one to practice with). I would consider them emergency backup only. They work, but are nowhere near as good a larger firesteel. I have the Swedish Army model and a Blast Match and both of those put the smaller models to shame. But it depends on what you are looking for. A fine toothed hacksaw blade will improve performance, but those really eat up the firesteels much quicker than other strikers. Especially with the smaller models, buy at least two - one for your kit and one to practice with. I remember the BSA models being cheaper than the $7.95 your URLs show ($4.95 or $5.95 possibly), but then I had to drive 25 miles round trip to get the the Boy Scout store and with the price of gas, you may be better off with an online order (depends on shipping charges).

I bet the main difference between all these sparkers will be the size of the rod, larger dia. rod = larger spark.
I like the BSA rod, the the size Vs. cost Vs. spark it is tough to do better.

I think that is the Swedish Fire-steel answer to a Jukkasticken.

Tip: The trick will all of the small ferro rod's is to place the end of the rod into the tinder. The trick of drawing the rod back against the knife only works effectively with the full sized rods.

With small sticks I always have plenty of Tinder-Quick with me. Saves a lot of time and frustration.

If you don't have T-Q's use cotton wool.

I have several 'regular' Light My Fire firesteels and I think they're already pretty 'mini'. I'd like to have the military sized one with the super beefy rod but they're hard to find and 3 times the money.

Hacksaw - beefy and long Swedish firesteels here. Also hacksaw blades work very well with these, I prefer to use the smooth side of the blade. With these extra long 4-inch firesteel the sparks are big and very hot because the scraping surface is so long.

I have a Swedish fire steel carry and use it often. The one thing I don't like is the striker is small, but it work. Other than wool or cotton you should carry some rope, char cloth with it.

Pull the rope apart to make a tinder nest and the char cloth will take a spark and hold it right away, once placed in the rope tinder nest and a few blows you will have fire in a matter of minutes

I have the mid-size and mini fire steels (but have used the larger size too). The big thing about the little guy is that you obviously have fewer strikes. My guess would be 1000, depending on how aggressive and hard you use the striker. The mini came about because one of the editors from Backpacking Light asked the manufacturer to downsize it for ultra light backbacking. The smaller one means you have to be a little more delicate and deliberate with the firesteel than with the larger models.

I keep mine on my keychain and put the striker in my archive storage. It isn't that the striker doesn't work as well because it does - I just elected to not carry it on my keychain with the rest of my stuff. I can use either a carbon steel knife or the edge of my lock on the lockback knife to create the sparks. I think using the edge from a hacksaw blade would use up the ferrocium quicker because of the teeth but I don't know if you would get better sparks.

I've used it on my camping stove and a couple times on tinder with good results each time. I used a bit of plastic tubing from my aquarium supplies to wrap the ferrocium rod but found out that it really isn't necessary and it makes it slightly less friendly to use.

I've heard of people who have had difficulty using these strikers but it always comes down to the fact that they aren't using it properly. A strong swipe of the length of the rod instead of a quick hitting strike will always yield better and more sparks.

I have hacksaw blade pieces on all of my firestarters that didn't already come with good ones, primarily the magnesium and ferro variety. I use the toothy edge on the magnesium. The back edge gets squared up on a file and that gets used on the ferrocerium rod.

Anything with an edge that will scrape off some of the rod when scraped against it fast enough will throw sparks. Broken glass works very well, especially if you can actually find a piece from a thicker bottle. If I need to mention to anyone to be careful handling broken glass, then those folks shouldn't be setting anything on fire or even on the internet.

As to the original topic of the thread, I have two of the large "army" models. I put the "'s in there because they weren't touting that connection when I got mine, I just knew that I had a choice of large or small and I picked the large model for the greater shower of sparks. I haven't had a single complaint so far over several years. I've had some ferro rods turn to dust in a week it seems and others that hardly corrode at all (at least in the KY/IN/OH area). I check the one thats packed whenever I check the pack and it still looks fine.