Just flew SU, they are a regular modern airline, with new planes, these are my note...
1. No vodka or whiskey allowed to be drunk on board, (they don't provide any... only wine and beer) poor beer selection, juices are Russian company so no Kosher certification.
2. Wide selection of lounges in SVO that can be accessed with Priority Pass which include showers and massage chairs (In the Gallery Lounge).
3. KSML not the best, (Hamasbia from TLV was probably the best...)
4. Take this seriously, they are extremely strict on carry on sizes and weight, they check every bag and tag it, so if you don't have a tag you can't take it on board.
5. Their A321 (TLV-SVO) doesn't have any entertainment systems in economy, so prepare something to listen, watch or read in case you rely on their entertainment systems.
6. The staff on the plane (not on the ground) is very polite and friendly.
7. People in Russia speak very poor English (including on the plane...), so be ready that most people in the airport won't understand what you're talking to them and just ignore you and walk away from you...