If you're 700+ in, might as well.
There's a "No going back" point when it comes to super rares and you've already long passed that.

Who knows, you might be the lucky few that popped it at 780.

However, if power is important to you, always choose that. As it's something that generally makes you stronger. Ninjas > Power only if you're a casual collector.
In the end, though, it's up to whatever makes you happier.