Less powder is not necessarily a good thing. In fact, it's been shown over and over and over that the more you fill the case, the more consistient your ammunition will be. I used to try to save money by using powders that required less (on paper) to do the same job. In practice, they did not, and the money saved was negligible. 231 is a good powder that fills the case fairly well and meters very well.
Unique works ok, but meters like mud in my equipment. All this being said, 231 and unique are both do - it - all powders which work ok over a variety of calibers and applications and like all one size fits all items, seemingly are never the best at any one load. If I had to use only one handgun powder it would be 231 though.