I flew them a couple of years ago from Moscow to St. Petersburg on an older Tu-154 and found them quite acceptable. It was worth it just to experience a Russian aircraft and watch people fold the seats forward as they got off the plane.

Service was actually better than AC with complimentary meal and alcoholic beverages on a flight that is the equivalent of YYZ-YUL.

Note that all of this is likely a moot point. Although Pulkovo might be the "official" airline of the conference, they do not fly to/from North America, so if you're gonig direct from here you'll need to fly Aeroflot or connect with LH or some other European carrier.

Bottom line - give it a try if you can - flgihts within Russia are pretty cheap.