Cathy ... If I have the yardarge I try not to piece it. But it also depends on how wide the border is going to be. I'm not going to buy 108" of fabric for a 2" inner border
If I have a wide border and it's a big bold print and piecing will be obvious, I'll either buy enough yardage or try to match the print.
If I have to piece it, I prefer to do it on the diagonal.