My experience with short barrels on my phantom is a love/hate. They work but affect the consistency of your chrono. I've found that the longer your ball is controlled as it exits, the more "ball on ball" accuracy you'll achieve. Not really scientific, but a reasonable observation. It's also easier (for me) to get that point-n-look accuracy with a longer barrel. Ill use either my stock phantom barrel or the my 11" dw cci barrel. I like both. Preference of the barrel depends on my paint size.
Gotta find what works for you. Some guys are deadly with micro phantoms regardless of how they gotta lob a ball at you.