Need some HELP choosing the BEST Interactive WhiteBoard

I am currently investigating different Interactive Whiteboards to . I am looking for opinions on which board has the best supporting software to help boost engagement in the classroom. I would appreciate any opinions or personal experiences with a few different brands. Anything you can tell me about the ease of use, the pre made tools that are made available to you, and the advantage or disadvantages of the board would help tremendously. The 5 I am currently looking at are SMART boards, ActivBoards, PolyVision, Mimio, and eBeam.