I have no experience with these three. 

Ordered 8# of Longshot yesterday since it seems like people are using it (and it was avail at PV).

My understanding of True Blue & AA#5 are faster burning powders. Although useable in many cartridges and a little can go a long way, it has limitations as pressures increase.

The Hodgdon's LongShot seems to be one of the better powders for delivering higher velocities in many cartridges.  But to get what velocities like those of SwampFox and Underwood it has been loaded beyond the published data.  Just understand the risk vs the rewards at the extremes.

Not sure what all cartridges you load for but it can be used across a good spectrum of calibers.

for 10mm. I know that Quickload very conservative (too safe if that's possible) they seem to map out together.
HS-6 is also in there. I need to get the chrono set up. Been using Power Pistol, 800x and Silhouette.

Like shadow says...aa#5 and true blue are too fast for 10 mm except for very light bullets.

Long shot is a great powder though.

8 grains of #5 under a 180 makes a really nice "FBI load" for gaming or for handing your G20 to someone who is recoil averse. I've run that combo in a number of IDPA matches and other shooting games. I wouldn't seek the upper limit of this powder in 10mm though. LS is better for that. I have no experience with True Blue, but I'd treat it like A5 if I did load it.