I like spp 45 brass because
1) Its free and only about 20 of the 150ish pieces of 45 brass each weekly range trip are spp.
2)it primes waay easier
3)It gives you options if you run out of large pistol primers. small pistol primers? sure! small rifle? have at it! small pistol magnum? pop em on in!
4)I keep a box of spp ammo in my range bag. its loaded with tula srp(copper color) that way If im ever shooting next to another 45 reloader at the range, I can easily spot my brass without question. A sharpie in the range bag to run down the case heads does the trick as well I guess.
Long story short: I like em
I still havent ran across a piece of amerc brass. in the last year I have collected 5,000 38spl, 1,000 357 mag, 1,500 380acp and 2,200 45acp. I have ran across a few tula 45 and 380 pieces of brass. those are cool.