I'm from Salt Lake City, Utah, and I say "ant."

My wife is from the San Francisco Bay area, and she says "ant."

I have never heard a Westerner say "ont." We live in Virginia now, and once in a while I hear someone say "ont." People don't typically talk about aunts in Virginia--they talk about property values, which is far more annoying than "ont."

I lived in Rhode Island for a few months, not long enough that I remember anyone saying "ont" instead of "ant," but long enough that I remember a few people saying "con't" instead of can't.

Merriam-Webster lists "ant" before "ont" but does list both pronunciations. For can't, it lists three: can't, "con't," and "cain't" ("especially Southern" it says).

Finally, I find "ont" mildly annoying but not worth complaining about (except when anonymous on the Internet). :-)