Bassbarber,
7250's are nickel plated steel RW, 7150's are pure nickle RW, I've used both as well as 9050 flats, and never had a problem with Fender strings. Good value. IMO 7250's are a modern aggressive sounding string, easier on your frets than stainless. 7150's on the other hand, are more of a mellow, vintage sounding string, well suited to blues/r&b. Some where between flats and round steel. Your frets will like these, and so will your fingers, they feel slick and don't squeak. Both decent strings. I would recommend the M sets as the lighter ones sound a bit thin to me.
I just learned that Fender now has a new string supplier, some who have used them are convinced it's D'Addario. Not having tried the new strings, what I wrote above is based on the old formula strings.