The browser itself is slow and buggy. It takes a long time just to get to the page you want to cast. Then, it often has trouble detecting the Chromecast, meaning you may have to reboot the Chromecast or reconnect to wifi in order to enable the connection. Then, the browser app likes to default to Google and jump down so that you cant type in the address bar. It also offers a delayed response to most screen taps, so if you tap twice, expect it to think youre clicking something unexpected. But when you finally convince it to go to a site and cast, its ok.
Paul E Graph about CastNow Browser for Chromecast