Not Nice - Not Nice at All.
If Life can Evolve on a Jupiter-like Planet - and develop into Intelligent Life, they would be tough as hell.
However - saving Graces -
They will need VAST amounts of Power to get off thier Planet.
They would need incredibly STRONG Space Ships to hold their Atmospheres.
A Sci Fi Author did a Novel on that - A Jupiter based Civilisation. Once they find out that there ARE Other Planets, and DIFFERENT types of Life on them - they go all-out to Destroy what they regard as Alien and Unacceptable Life-forms - How DARE They even Exist !!!! Worse than Rabid Racism - worse than Xenophobia.