if you say that your abs could feel "a bit stronger" then they'll probably just automatically strengthen to the appropriate ammount as demanded by the exercises you're using, unless there's a serious deficit.
as for you primary question, your comparison was between a specific exercise vs. a specific muscle group. that's kinda like asking whether a specific car is better than a transmission. you need to offer 2 exercises if you want an idea of ratio.
overall, you should just probably do more planks and call it a day.