They both get good reviews. I have not had difficulty getting the 120NBT to shoot well with multiple powders in my 260's including W760, H4350 and H4831SC. Have not shot near as many 120SPH but they shoot good too. The NBT is definitely a tougher bullet IME
Check the reviews on Midway. You have to wade through the NBT but there is plenty of info there for the 260 and similar cartridges.
Good luck and shoot straight y'all
https://www.midwayusa.com/product/1010525454?pid=517478https://www.midwayusa.com/product/1010508373
