Never talked to my undergrad professors. Talked to a several of my grad professors. They all encouraged me to apply. I told them I didn't have a strong undergrad background but I never felt like they really understood the extent of it because they only knew me if via their courses and experiences. We didn't really talk about specifics though (what my gpa was, what school I wanted to go to, etc). The vibe I got was TAing the courses I was TAing would be my ticket in. The TA before me (though she had a very different background) ended up going to Yale and got into everywhere she applied.
I tend to disagree with the professionalization point, could be off on that though. My masters is actually in IR (the subfield I want to pursue along with methods) from a "professional" school. While that isn't viewed as favorable, I think they will appreciate some of the skills (namely, wicked stata programming skills) I picked up, as well as the field research methods stuff. At least at where I was (UCSD) the general vibe is that the field as a whole is moving in the applied direction. They don't want people that can write long narratives, but people that can crunch numbers and run regressions. That is just based on the vibe I got from one school though.