If you had these 2 powders, which would you use for 9mm 115gr JHP bullets?
My guess is it is a wash, but I appreciate your thoughts.

Have them both for that same loading. I've stayed with Unique, principally because my gun is cleaner at the end of a shoot, I think. It's been a long time ago that decision was made so I really don't recall details of the choice. Been too long since using Blue Dot but may use it if I can't get more Unique. Just this AM got down to the dregs on the last can I have.

Edit: Why not post this in the Handgun Reloading board? Might get more action.

Just found a little AA Solo1000 and AA#2. Don't know if those are any better.

I'd easily pick Unique over BD, which I do like in a bigger case, like a 41 mag. Unique is pretty close to PowerPistol which is my favorite for 9mm.

As for Solo-1000, I love it in 45 ACP, as it's accurate & very,very low flash, but never used it in a 9mm & the loading would be small, very similar to Bullseye.

Never used AA #2.

MM

AA#2 is similar to 231/HP-38, perhaps a fuzz faster. I used it for years in 9mm, 10mm and .45ACP, as I was working in a gunshop and could get the kegs CHEAP compared to 231. I had good working loads for all three chamberings, and it was fun to use, with a somewhat "softer" recoil impulse compared to 231, with loads that were similar in performance. Yes, I used it in 10mm loads, too, that duplicated my .45 IPSC loads (200 SWC@950). Lots of fun.