I emailed Mobil on whether or not they used esters. I know their tech staff isn't always great, depending on who you talk to but this is what they said. I brought up Redline as well. Couldn't resist.
Mobil1 motor oils utilize synthetic basestocks; along with PAO's, synthetic esters, and alkylated napthalenes. Mobil feels like you must have a chemical balance of basestocks and additives to have the most superior product. Redline is a very good product; however nothing outperforms Mobil1 motor oils.