Have used H4350, RL-17, RL-16, Superformance, IMR4350, and Varget. Even surplus WC852.
They all have pros and cons:
1) IMR4350 performed almost identical to H4350 but needed 0.3-0.4 gn more for the batch i was using. Shot the 140s and 140s very well. Same group size. Slightly temp sensitive, but not terrible.
2) Superformance shot 120s, 130s, 140s and 150 well at very good speed (around 120 fps faster) but the loads are compressed (i used an ultrasonic toothbrush to settle the powder before seating, still crunchy). Temp sensitive.
3) RL-17 was fast and accurate but very temp sensitive. Need a winter and summer load. About 150 fps more speed. Good groups. Some concern that it eats barrels faster than other powders.
4) RL-16 was remarkably accurate in my MPA rifle, gave adequate speed and shot tiny groups of around 0.10” at 100 with 135 gn weight sorted Atips. Amazing accuracy. Cannot find any!
5) Varget was accurate but speed was about 100 fps lower than H4350.
6) Surplus WC852 surprised me: It gave 1” groups at 400 while fire forming brass. Remarkably accurate with cheap Hornady 140 gn BTHP bullets. It was very cheap, but it is hard to find this powder now. No published load data. I loaded low and never looked for a max load, around 2500 fps with 140s.
Apologies: My MPA rifle has a min spec chamber and shows pressure signs around 1-1.2 gn lower than my sloppy chamber R700, so no point in publishing my load data. I always have to stop well below book max.