Have mine set to check for new versions, mainly as there are new codecs etc. coming along all the time. Haven't noticed any ads other than clickable links to the Tektronix website, which don't bother me.
Sorry guys, I was mistaken about the adware. About two years ago my anti-virus software complained when I wanted to download the "installer" version. I now have downloaded the "non-installer" version without incident.
MediaInfo is such a useful utility, just donate a few bucks since it is so useful and you get download links to a installs without any ads or donate button.