Via HDMI there was a very very slight delay, but that's not there via RGB, interestingly. That's with the computer.. with the XBox over component I don't notice any.
The main differences, as far as I could tell, were:
1) Vizio bezel is ***-ugly. Looks like cheap, warped plastic.
2) Vizio has two HDMI inputs, Maxent has one. (note: Monoprice has HDMI switchers for ~$100)
3) Maxent has noticeably better blacks
4) Maxent has removeable speakers
5) Vizio has an exhaust fan that is audible many feet away, and has a known issue where many sets have an audible buzz. Many people have gone through several sets to find one that doesn't buzz.
Ultimately I bought the Maxent for the plain "picture frame" bezel (wall mounted) and black levels. The picture quality is really about equal.. which is to say fantastic.
One other thing to mention is that analog TV on the Maxent via component is total crap. Fortunately, my cable box is capable of upconverting everything to 480p or higher so it's not an issue at all. S-video looks fine, though. I know some people are using component for 480p and above, but S-video for analog stuff. I don't have any analog sources.