I love Donnelly MXPs. They are a good all conditions tire.
I previously ran Donnelly PDXs, Bontrager CX3s, and I think a Vittoria before that.
I found that the MXPs excelled in a wider range of conditions. I have friends that swear by PDXs in all conditions but I found the only thing that PDXs are good for is shedding mud. The MXPs had greater grip in corners and less rolling resistance in a straight line.