*sigh*
Unique is a perfectly acceptable powder to use in .44 Magnum with bullets of a normal weight. Quite popular in many cartridges running that sort of pressure, in fact.
It's also a medium-burner, not a fast powder. On any burn rate chart, you'll find it occupies a spot dead center between the fastest handgun powders, and the slowest. Which is precisely how Alliant designed it, falling in between its siblings Bullseye, and 2400.
The advantage of Unique is that it pushes a 240/255-grain LSWC--the most popular .44 Magnum bullet by far--to a respectable velocity, all while metering well, being much more resistant to squibbing than 2400 or H110, and taking 1/3rd to 1/2 the charge of a slower powder.
If you want to push a jacketed bullet, or use a 300-grain thumper, you'd probably be better off looking at something like H110 or 2400. But by then, the advantages of Unique likely no longer interest you.