Como usted está con nosotros más de dos años.
Because you have been with us for more than 2 years,
Como vs Porque

Ava Dawn
August 15, 2014

Steven-W15
August 16, 2014
This tracks pretty closely with English: "because" vs. "as". I think a better translation (and better English, quite frankly) of the above sentence would be:
"As you have been with us for more than 2 years..."