Pretty great. I grew up there, and now live in a city adjacent to Plano.
Pros: Quiet, affluent, good schools, wide streets, nice people.
Cons: Sometimes it’s a little too quiet; everything closes early. Unless you’re on the east side of Plano, the Plano society is known a little uppity. Plano is surprisingly large; so, it takes like 30 minutes to drive from one end to the other (i.e. E-W, not N-S because most highways running through Plano travel N-S).
When I was growing up, Plano was a little far from anywhere fun. But since then, the Shops at Legacy have blown a breath of hipness and modernity into the city, and the city seems to be developing northward. Property values used to be amazing, but there isn’t much available land anymore, and a lot of people are moving to DFW now. So, values have likely appreciated significantly since I was younger.