"The repeal of Don't Ask Don't Tell has had no overall negative impact on military readiness or its component dimensions, including cohesion, recruitment, retention, assaults, harassment, or morale."As a relevant note, the research team used "vigorous efforts" to collect data from all major military and non-military opponents of DADT repeal.
-From "One Year Out: An Assessment of DADT Repeal's Impact on Military Readiness" (PDF), UCLA Palm Center
If you read the full report, feel free to discus it here.
[**See note on word deletion]