Well, growing outside in South Florida I see lots of ants!
I don't usually care if they are on the plants. They are good for one thing: they will lead you to the scale, aphids and mealies. I do get rid of them if they are forming nests in the pots or if I see them carrying eggs.
I have stumbled upon large colonies in the roots when watering (especially submerging) before.
That is very disturbing and I usually just spray the heck out of the roots and pot with Raid right that minute
, then go back later and rinse it really well with fresh water. That has never hurt a plant for me.
For regular ant control in and around my house, I always use Terro. Since it is a bait, it will draw the ants to it at first. So I like to put it just outside the house (if I can find where they are coming from). That way I don't have to look at them when they descend on the bait. yeech!