The core of the video conferencing cart is the video conferencing unit that both displays your remote meeting participants as well as transmits video of your end to the remote participants.
Some capabilities to think about:
Single screens are more cost effective and can be split into “virtual monitors” to display slide decks and video simultaneously, but do not offer the same impact/scale as two screens.
Multi-point capabilities will allow you to bring in people from more than one location into a single conference.
Larger rooms may require more microphones so that everyone on your side of the meeting will be heard at the far end.
Video units can provide a vast range of video qualities. Most video units by default offer high definition conferencing.
The highest quality video conference will suffer from a slow or congested Internet connection. Talk to your network administrator in gathering needs for your video cart.