"We'll let you know who's calling, based on previous call data, and algorithms." - made me laugh
One suggestion - remove the "Powered by WebRTC". I doubt your customers know, or care, what that is. Perhaps, instead, replace with a "No Hardware to Buy" type of headline.
"Powered by WebRTC" means, to me, "we aren't going to charge you PBX prices" and "no need to install 3rd party software that may or may not work for each of your agents". If this has a competitive pricing model and support for Android we're in.
I second the removal of the "Powered by WebRTC" paragraph. You might wanna test a version of the page where the copy focusses a bit more on selling the benefits instead of on the features.
Interesting product, though some of the language in the video and on page felt a little awkward.For example, the voice in the video says "just not only that!..." I don't know if it's just me but that does't seem right?
On the front page, the image of the laptop is ON TOP OF the sign up button, so the right side of the sign up button cannot be clicked. Move it to the back. Great startup btw, I can't wait for launch.
Cool service but the color choice as a weird vomit yellow for two of your feature icons is pretty awful. I suggest keeping it consistent with your blues. How about #1984A2.