You also get wider fork stanchions (30mm vs 28.6). Those will make for a stiffer front end, and the fork is probably somewhat better too.

And there is nine-speed on the spendier bike. Nine-speed and the shifters are separate components from the brake levers, which I prefer because then you can replace them independently.

I know you are on a budget and need to consider other expenses like a helmet and so on. If you can swing the extra cost of the sport model you get a better fork, hydro brakes, nine speed, and a few other component upgrades. In the long run you'd probably be happy you spent the extra for the nicer bike.