Has anyone done this, or have any info regarding it?
do you think it is a good idea?
I haven't done it but looking at the ferry schedules, you leave at 21:15 from Genoa and arrive in Barcelona at 15:15 the next day (18hrs). Fare is about 140Euro for 2 people.
You might look at flying to Barcelona from Milan or Pisa. Vueling and Easyjet fly from Milan and it looks like only Clickair flys from Pisa. Less time and most likely less money.