OK, so I didn't fly this one miles and more, but I was on a different Star Alliance carrier. But as the route is covered by Austrian and Lufthansa, and there is only one (shared) international business lounge, and one (shared) international waiting area, I hope that you will enjoy this review.

Business Lounge: Terminal B (international terminal) (although they are building a new terminal next to it, so it may change next year!)
Through the customs, do the check-in desks, past immigration
(Yes, that's right, you do customs, then check-in!)
Turn left for business lounge (turn right for main waiting area).
Lounge is small and rather dark. Mostly Russian language publications. There is a bar, and the girl on reception will remind you of your flight. About 5 groups of sofas/armchairs, and a table with 4 work chairs round it. A large screen TV is against one wall - it was showing Russian cartoons when I went in.
Quite peaceful.
Bit dark to read properly, though.
If I had had a laptop with me, and a few batteries, it would be a good place to do a bit of work.
NO INFO SCREENS ABOUT FLIGHTS!!
As it was, I got bored, and went to the regular (economy) waiting area, which had a good view over a section of Runway, and I could watch the BMI plane docking etc., and it had info screens^

Baggage handling: In SVX, all but one of our bags (all "priority" marked) came off quickly, the other bag was one of the last on the carousel (Mrs G was starting to worry that it wasn't going to arrive!)

Tips at SVX: Don't expect the customs and security men to speak any English at all, and don't expect official notices in the airport to be in English!! Get a good guide book/ learn a bit of russian/ see if you can find a bilingual passenger on your flight!
(Mrs G and little Miss G speak fluent Russian, so I was well covered)
Remember - you have to go through customs before you get to the check-in desks at svx, and expect to be security scanned as you enter the airport terminal (as well as at customs).
For customs - you only need a declaration form if you have anything to declare - if you just have regular souvenirs, just go through the Green Customs channel.
You must declare cash over a few thousand dollars, and if it is more than about 10 thousand, you need supporting paperwork. Check this, as it may well change for year to year, and the Russians seem to like changing regulations without apparent notice .