What is the best NACES organization used to either translate or convert foreign college degrees/transcripts for service members?

I am trying to apply for an OCS Board at the moment, and I received my graduate degree from King's College London in the UK three years ago. Are there any service members who have had to use NACES to convert their transcripts, and can recommend the best member in terms of price and timing for service members? Everything on my transcript is in English, and I just need to get the actual grades on my courses converted to the American grading rubric.