Personally, I would use both if I had the access. I always double-check any fact that looks
dubious on Google. However, in many cases, vandalism in Wikipedia can be reverted in minutes,
even in a few seconds if a regular Wikipedian happened to come on a page that had just
been vandalized. The fast vandalism reversal is the reason that Google trusts Wikipedia so much,
I think.
However, sometimes Wikipedia can have too much information. If I need some simple info, I
sometimes find a huge Wikipedia article. To me, Google is the ultimate source. You can look
on several websites to fact-check quickly.
Actually, now that I am done with my post, I don't really think that I am talking about the same thing.
To sum it all up, use what works better for you. Google works best for me, and I think that Google
can beat both Encarta and Wikipedia on some subjects.