Casting from a phone makes streaming slower
The handshake between your phone and the Chromecast itself, which is the most time-consuming part, still takes about the same amount of time.
Compared to a Roku, Chromecast isn't the fastest way to watch video on your TV: you'll need to unlock your phone, open the app, then press the Chromecast button and then wait a few seconds for it to appear on the TV. With a remote in hand and onscreen menus, in comparison, the same process is much faster on a Roku or Fire TV.
In my testing, serving media from an app consistently took between 7 and 8 seconds to appear on the TV. I loaded YouTube and Netflix on an iPhone ($899 at Amazon) and Hulu on a Nexus 9 and the result was the same. I didn't really notice the 15 percent speed boost; the 2018 Chromecast was roughly as fast as the 2015 model. We have reached out to Google for more clarification on where users will see improvement between the two models.
Voice requires a Google Home speaker
The pace of change in TV streaming hardware isn't as drastic as in other areas of tech, but living room voice control has evolved a lot. Amazon incorporates a mic with Alexa into Fire TV Stick remote, but you need a separate device to get voice control to work with the Chromecast -- either a Google Home ($99 at Target) or phone.
Using a Google Home, I asked Chromecast to play Netflix and it sometimes worked really well. Other times it didn't always understand what I wanted to do, and occasionally muddled video requests with web results. For example, I asked to play Orange is the New Black with the TV turned off and the dongle plugged into the ARC port -- and Google turned on the TV and played fine. However, when we requested it to "play Pokemon", instead of playing the Netflix show we expected, the assistant gave us a description of the "Play Pokemon' tournaments.
Aside from the "streaming content" thing, two of the most useful features of the Chromecast are voice-control compatibility and HDMI CEC (power and playback control), and using them together holds the greatest appeal for this device. You can theoretically ask Google Assistant to play music and HDMI CEC will turn the TV on and play. Of course, this will work fine if you have just one Chromecast plugged into your TV and nothing else. However, once you start to add other HDMI devices or a sound bar/receiver, you'll need to make sure everything is set to the right input first, spoiling the magic a little.
As we saw with the addition of voice control the Chromecast itself is still in flux, and there are changes on the horizon. By the end of 2018 users will be able to create a multiroom audio group incorporating a Chromecast, and this is something users have been breathlessly anticipating since the Chromecast Audio was released. However, you can still serve music to it alone right now using apps like Spotify.
Should you buy it?
The short answer is no, because Chromecast hasn't done enough to stave off the competition. If anything it still feels like an ancillary gadget -- it shouldn't be your main streamer, unless by necessity. Asking Google to play video doesn't work as smoothly as when requesting music, so this isn't the product we'd recommend to people buying their first streamer specifically for voice control. Fire TV wins the voice race, and the basic $30 Roku Express is still our favorite budget streamer overall.