Hi Joey, 5.7x28mm is way more expensive than 9mm, so if you plan on doing a lot of shooting, 9mm is the way to go.
Stay safe & have a great day!

Hi Joey and welcome. The 9mm model will likely be the best overall caliber over the 5.7 x 28 which is regularly compared to the 22 Magnum. I got caught up in the 5.7 x 28 hype years ago but have long since relegated it to the novelty category. If target and plinking is your primary use preference, then by all means partake. Cheers, stay safe and enjoy!