Do I trust Britannica? Do I trust Wikipedia? As in using either for a single, definitive source of information? Absolutely not.
I've also not had to write a term paper for 20 years, so any "pedia" use for me is purely out of curiosity.
If you are trying to claim an open source/community contributed project like Wikipedia is just as soild of an info source as a closed source, there's simply too many factors to figure in. Cite Wikipedia in a term paper, I dare you
Jerkoff Wiki user #1 decides to deface a Wikipedia entry. Let's say it's an obscure Wiki entry where the original contributors no longer look after it, followers of said content are few and far between. Jerkoff Wiki User #1 could deface that with all sorts of bull**** and it might not be noticed by anyone for 2 weeks, except some poor kid writing a paper based on the information. The flaws and benefits of Wikipedia style affairs are pretty clear. Flaw - everyone can contribute, and some dick can put false facts. Benefit - up to the minute updates on entries, assuming they are fairly popular you can assume they are relatively accurate. A new vs. old media mindset to some degree? Sure. What is great about Wikipedia is also what is wrong with it.
Drawbacks of Britannica type things are few, but if you are daft enough to assume they only update online materials once a year like the old print versions, you are wrong. Is it up to the minute up to date as Wikipedia is? No. But it is fact checked, and inherently cite-able. The Britannica won't tell you who Beiber is dating right now, or who's banging Paris Hilton this week. If I'm looking up detailed historical data that I can actually cite without my Prof laughing me out of the class, I ain't going to Wikipedia.