We Live by Our Own Code. What’s yours?

I finished a purchase loan transaction with a client living in Southern California. The transaction went smoothly enough, but my customer asked me a question that I was not sure how to answer. "Did I think it was in his best interest that his realtor was not only representing my client who was the buyer, but also representing the seller as well?" Out of the realtors I've worked with, many have been able to handle a transaction of this nature and do an excellent job. Other realtors I have worked with frown upon representing the buyer and the seller within the same transaction. I am the loan officer and although unbiased, I would like to know what the popular thought is among realtors concerning double transactions.