under_dawg, I've burned a pretty good amount of True Blue in .40 S&W loads. It's the most accurate powder I have used for that, but Silhouette comes pretty close and because it's treated to have very low flash, it's what I would use for making my own defense loads. I very much agree with Handloader's
opinion that medium/medium slow powders are best, so I don't know how TiteGroup found its way into their testing. I would never use TiteGroup in high pressure cartridges myself and particularly not the .40 S&W. AA#5 is the fastest powder I ever used in .40 and it can be considered a medium burner. Power Pistol can deliver the goods velocity wise, but at the cost of very high muzzle flash. WSF has always had a good rep for all-around performance in .40 S&W. Two others that I burned a lot of with very good results that gave low flash were V-V 3N37 and the no longer available Vectan SP2. HS6 is decent but pretty much superseded by Silhouette which is one of its offspring where I believe Primex, now St. Marks, was trying to create an equivalent powder to 3N37 when they developed WAP which was the forerunner of Silhouette.