I took a business colleague of mine on an SU flight ( we travelled Business Class). He had has just arrived on a Rossiya flight a few days prior also in business class, and he was astounded at the difference between SU and Rossiya. The Rossiya flight attendant barely spoke English, not sure how she could work an EU flight.

In economy the quality is mostly the same between SU and Rossiya, but in business SU is a much, much higher category.