I have used New Holland (the link is actually partspring.com when opened, not New Holland) up in Washington mainly because they are closer to me thus lower shipping rates.
I don't know about rates but if you order something from Messicks it seems it's out the door that day. I've ordered several things from them by phone. It seems the delivery man is at my door when I hang up.
But then they are also so darn helpful and polite.
I've used Messick's for several purchases as well as asking questions of their knowledgable staff. I'll use them everytime for OEM parts! They are far better than my local NH dealer.
Still, I couldn't help but comment on the self promotion.