Would you have a LTR with a girl who is into you, you like her, she is okay but you feel you could get a better one?

My brother had at least 5 relationships over the last 10 years like this because these are easy targets, he doesn't really have to work for them, he is naturally good with girls. He always ended up with creeps/girls who are definitely not on his level (especially mental, emotional, intelligence level). I saw many other similar examples.

My suggestion: RUN!!!

What is your experience?