1/4 acre in 2 hours? Is your lawn a maze or something? That's really slow.Do you need self-propelled? No.
Are you going to wish you spent the extra $50 for a lawn mower that had it one day? Absolutely.
I mean, you can still push it if you want, but it's really nice to let it push itself. Especially on hills and shit. I leave mine on the mulch setting and just coast through the yard, only 1/4 acre and it takes me 2 hours.