The video seems to show that the two browsers are fairly much comparable. I do agree, however, that the two things that the Android browser shines at, zooming and scrolling, would be nice to have in MicroB too.

Best line in the video: "Microb can do [portrait mode browsing] too, but it requires some hacks."

Unlike the Android browser, which requires no hacks at all. Strange, you didn't seem to give a link to the .deb for installing that browser...