Well I definitely don't know a whole lot about the specific processors so don't quote me there. What you said is what I do know, is that the MTK is preferred over both the ATI and the Pixelworks. So that's why I just said they are a push.
What I am going off of is I recall reading threads saying the Pixelworks was just OK, and the recent stuff on the ATI with SD problems. As far as what I've seen with my own I eyes, I have a 227V (ATI) and I do notice some blurring with SD stuff. But it is really on a channel to channel basis, DVD to DVD basis. I just have it hooked up through coax on the wall outlet. All in all, I still say I am quite happy with it.
I am also interested in testing it on my HD DVR out in the living room thru component (or HDMI, I'd have to buy a cable though) to see how it impacts the regular SD quality. I'm really just too lazy to unplug everything and take it out there.
To me, basically your choice lies in how you are going to use the TV. If you are just going to get an STB anyways, then the 332H comes a real option for you. Otherwise, I prefer having the TVs (232's, 432, 532) with built-in tuners, not forcing me to get a box if I want to use it as a second or third TV. The QAM is also a nice bonus as I get to watch all my locals in HD w/o a box or antenna on the 227V in my bedroom.