The utilities getting shut off is more realistic, but right now there are no real consequences as the sim can pay the bill at any time and there are no "reconnection fees." I liked the repo man as the sims would go so crazy and it was a funny sequence.
I think the utilities shutting off would be better if there was more lasting consequence - like late fees, a delay in the utilities getting turned back on (like they have to wait for 2-4 hours) or an embarrassed moodlet, or something... (maybe our sims need a credit rating?! Ha!!).