My Take
Real quick to set up and the introductory video makes navigating the site a breeze. Some features can be buggy at times such as the power point add on and clearing poll results. The fact that some real useful features (i.e. summary reports and user identification) cost money may turn away some users. Also, the free version only allows for 40 participants at a time. :(
How I Use It
Participation
Quiz (keep it under 6 questions)
Data Collection
Review Hook/Exit Slip
Silly Survey
Discussion
Anticipation