There are cheaper strings out there, but at the end of the day, I gravitate back to NYXL. They immediately feel right and sound great. I cannot judge the long term performance in comparison with others, but surely the honeymoon period right after restringing, these strings rock.
The 64-9 is excellent for fanned fret (Standard E with A in bass), but I will also go for this set for my normal-fret 7 string. The soft 9th string and the - fairly - heavy bass is just the way I like it, and the quality of the strings is impeccable. Its a keeper, from my point of view.