Neither is going to offer great or even "meh" gaming performance. Undoubtedly the GT 730, while a low end card, is better than the HD graphics, but the use of the FX-4300 kind of spoils the benefit. If you can include the GT 730 WITH the i3 build, it would be a bit better. What is your actual budget for this build and what components do you already have, if any?
Ah, I didn't notice those were prebuilt systems. My bad. I'd still probably recommend going with the i3 build because you can always add a graphics card later and have somewhat decent performance. With the FX chip you're going to be hamstrung no matter what card is installed. It WILL still work though, so it's really up to you. I'd recommend the i3 based on stronger single core and threaded performance, even though you'll be more limited in graphics until you install a discreet card later.