My vote for .357 mag. would be H110--15.5 gr.with Hornady 158 gr. XTP.... You will be shoot'in dimes at 50 yards!

Well, I have to vote Unique also. Yes it is dirty, but if you shoot, you have to clean, no matter what powder you use.

Unique fills the case nicely, while giving manageble recoil and desired velocities. I use it in my .357 with caste and Jacketed loads, and in my .40 S&W with Jacketed loads. I also use it for Shotgun shells - trap and med. hunting loads.

I have had no metering problem using the Lee Perfect Powder Measure or with my Mec 600 Jr. I cannot tell you how it works in progressive reloaders, I'm still a single stage kind of guy for rifle and pistol reloading.

I am partial to Blue Dot. I've gotten excellent results in .38 Special (normal, +P, and "Psycho Special" loadings), 9mm Luger, .40 S&W, .44 Magnum, and .45 ACP. The only real downsides it has are heavier charges due to its slow-burning nature, and a pretty bright muzzle flash in dim lighting. I found it to be reasonably clean in higher-pressure rounds like the 9, .40, and .44. It seemed a touch dirtier (but not objectionably so) in the .38 until I cranked the power level up to near .357 levels.

If ALL I loaded were low-pressure rounds, like (proper pressure) .38s, .45 ACP/Colt, then my nod would go to Red Dot. It's faster, clean, and meters reasonably well. It's also more economical, as you only need a small charge of it as opposed to nearly full cases as you do with Blue Dot.

2400 in my 357 mag 44 mag and 454

I just can't do it...but if I had too I'd pick unique if it was'nt so dirty. This is'nt a fair question. There is powder I have'nt tried yet.
Third vote for Universal Clays