"What scores are good..."
Actually that's as superb question. Unfortunately the answer...you won't like.
"It Depends."
Each person/candidate is different. And the "entire package" is what is scored, not just the SAT/ACT scores. So what might be a great score for one person might be "ho hum" for another.
I tell my candidates...if your ACT scores are in the 30's...you're very competitive. If your SAT scores are in the 700's...same answer.
Anything below that...keep shooting for higher! FYI...in 18 years of being an ALO, I have told precisely 3 candidates "your scores are fine, DO NOT take another test...focus on the rest of your package."
Those candidates had:
800M, 780V
35 ACT composite
790M, 760V
Yes, I'm a bit "demanding?" No, not really...I just remember how many times I took the SAT/ACT in high school (12 times) and I didn't make it until after a year at prep school.
If you can afford to take the test more than once...go for it!
Steve
USAFA ALO
USAFA '83