Question - Fonts for PSP vs PS

I don't have Photoshop at home, instead, I have PaintShopPro. Now, because I have Photoshop at school, I've realised that the font seems to be much smoother and less distorted with different sizes, as is with PSP. Is there someone who has both programs who can tell me confirm that or tell me why?

For example, I've heard quebelly many times saying she bolds the small fonts like Arial, but if I bold it in PSP, it looks almost pixely.

Thanks in advance to anyone who can help me out!