Mikhail started to teach my son around 1 year ago.
We have lessons 2x2h per week, and sometimes more.
At the beginning I was little afraid, if skype lessons are really evicient. However it quickly turned out that it is and that Mikhail is a very good teacher. He helps my son to choose openings repertoire, analyse games played, better understand middle-game,endings etc.
Since we started the lessons with Mikhail my son's ranking has grow immediately from 1360 to current 1698 FIDE ! His ranking on chess.com (blitz) grows from around 1500 to even 2050-2100 now. In the meantime my son qualified for Polish Championship in chess U-14.
So I really do recommend classes with Mikhail :)