The 27-year-old was presented with the supporters' player of the year, players player of the year, away player of the year and top goalscorer awards for his 22 strikes.
"No one had really heard of Michu before he came to Swansea. He looks an absolute steal now," Roberts said.
"He's been an outstanding signing. It's quite remarkable the form he's shown throughout the season.
"His goals have been vital to the success that Swansea have had this season."