Classic sci-fi is traditionally modern-problems oriented technical and social. Yes, it is not about credible characters, it is about ideas. Nowadays sci-fi usually treated as easy reading in fictional setting that makes the genre more flexible for experiments. That is what fantazy, and many contemporary Russian writers often write in both genres (sci-fi and fantasy) or even mix them up so it is hard to distinguish them. In the same mix often alternative history.

Here some of my preferences (a bit outdated) in both genres as I don't separate in contemporary literature in random order.

Lukyanenko is today's easy reading in sci-fi with acceptable literary quality.

Kirill Eskov - I can recommend two books actually The Gospel of Afranius and The last ringbearer. He used scientific approach to the Gospel and Tolkien's universe and gained nice action adventure novels. The first one may be too boring if you don't know well the background.

Parfenova - her debute trilogy contained all typical mistakes of the beginning writer but at the same time was of extreme quality and really refreshing. The books full of female emotions, that a techno&science&logic man like me was able to enjoy. Though the language is rich and intensive and can be hard to read.

...to be continue... maybe