"Somewhat rare." Also, as other commenters have mentioned. It's not so much the size of Jupiter but the size and the location of Jupiter that is unusual.

Actually, as far as I know, having a gas giant the size of Jupiter in our solar system is a somewhat rare phenomenon in the galaxy. Scientists have posited that it may make our solar system more likely to sustain life because large asteroids, and other celestial bodies that could easily lead to extinction-level events, are caught in Jupiter's gravity well. Jupiter is the shield for the inner part of the solar system.

Edit: typo in the final sentence.