Magfire seems to get more sparks but not with the included striker.
BlastMatch is easier to use if you want to use it one handed.
I think the MagFire give hotter sparks too.
Both work well.

I tried one of the WetFire Tinders when I first recieved my Ultimate Survival Deluxe Kit. Its the only time I tried it, but it was no trouble to light and burnt for a reasonable amount of time. The memory is a bit stretched to remember exact details, but I am going to get some more when I order another Deluxe Kit to throw in the car.
I always throw in a couple of different tinders into which ever pack/kit I'm using at the time just in case, and the Deluxe kit gets transferred to every pack I use because its convenient and all together.

Honestly I think the Spark-Lite is a better one handed starter than the BlastMatch. (at last, I found the Spark-Lites in Australia) I seem to be able to manage that better. If I was hurt, the BlastMatch might be a little bit clumsy.
But the blastMatch is part of the deluxe kit, and it does work well.
I have no problem buying it as part of the Deluxe kit, but I wouldnt buy it by itself. I did buy the MagFire by itself and I would buy another. I dont like the plastic end though, a little bulky. I would preffer to have a hole so I could use a key ring instead. That way it would be part of my EDC.