The difference between WAVE and WAVE + Lily are as follows.
WAVE supports Finger Touch.
WAVE + Lily supports Pen Touch and does not support Finger Touch. WAVE + Lily comes with 2 Lily Digital Pens to support multi-touch. WAVE + Lily offers ease of set-up and more precision.
If you're looking to use applications such as white-boarding and annotations, we do recomment WAVE + Lily (Pen Touch).