Never used Wistia but had a demo with them a few years back and I was struck by their really friendly sales and service people. Those kinds of cultural indicators are always important I find.
Pricing (http://wistia.com/pricing) appears pretty reasonable for what you get. A lot will depend on how much video you are streaming and what features you need (and your budget!).
Wistia has some cool features like collecting emails in your videos, calls to action, etc. and much more sophisticated analytics then you'll get from YouTube. (Note, other video marketing platforms have these and other features as well and the space is maturing rapidly, so I'd also suggest shoping it around).
What kind of video campaigns are you doing and what features are you looking for?