Determine best video webinar software to use

We need to determine which webinar software is best to use as a marketing tool. We would like to host a webinar that will enable us to play three or four 45 second to two minute videos during the session smoothly. (We tested webex and the video was choppy). It would be great as well if the webinar app would enable us to play video of the presenter when not playing one of the videos, although this is not a firm requirement. The attendance will likely be a few hundred people but we would like to be able to support 1,000 or more attendees if heavily subscribed We would like a high-level feature/price comparison of the best webinar apps to do this. It doesn't have to be very detailed or very pretty, an excel sheet is fine. We just need to identify a dependeable solution that can meet these needs along with common features like user chat, registration tracking, powerpoints, etc.