Everspin has been one of the major players in MRAM for a while. I wonder if they are using the Samsung process for their products. If I recall correctly I think Everspin was a spinoff of Freescale (formerly Motorola, now NXP). It was probably 7 or 8 years ago when I saw a presentation touting the commercially viable STT technology, and it always seemed to be just another year away.
It seems aerospace and SSD manufacturers(write cache)are pretty popular areas. It provides really fast write speeds combined with power loss tolerance and recovery of write logs and cache that DRAM and Flash alone can't provide. It's also natively Rad Hard and nearly "write unlimited" which makes it good for a lot certain niche applications where the budget can tolerate it because it ain't cheap (2MB is nearly $30 in quantity). [1]