Genova in July, bad or good idea ?

I wanted to go to Genova in July but my friend told me it's ugly and uninteresting so I dont know what to do.

I have like 3-4 days of holidays in July and I want to go somewhere where I can go by bus from my place in Lyon (France), somewhere affordable, where I can eventually go for a swim and not to crowded si Genova seemed to be a great option, I was thinking of doing a day trip to Nervi, another one to Camogli. What do you think? Is it a great option or is my friend right ?

Is it better to stay 3 or 4 days if I go? Is it going to be difficult to take the train to go to Nervi and Camogli because of the crowd?