I've tried more than enough powders in the .44 caliber to make my mind up as to what I personally like. I tried 4227, but the loads I came up with were compressed loads and that gave me inconsistency. I've never tried H110 or W296 due to the narrow load window.
I've settled on 2400 for the big stuff - I load it under 200, 220, 240, and 300gr bullets with awesome results. In my Winchester 92, I get 1750fps with 22.0gr of 2400 with a Sierra 220gr FPJ - and I stay in the black at 100 yards with iron sights. That's also a comfortable, accurate load from my Super Blackhawks. For the lighter stuff like HD, target loads, and league shooting, I use Unique. I use that in both 44 mag and 44 spl also with great results. Both powders give great flexibility and reliability.
Both powders for all loads like standard primers. There's no need to use magnum primers unless you can't find standard. If you do use magnum primers, you need to reduce the load or you may have problems.
Most importantly, be careful who you take load advice from. Even here. Be safe.
-MW