There are a few ways to get directions from your computer to a phone, but Google just added this handy functionality to Google search. Simply search for "send directions," and Google will let you pick a location and device, then you're good to go.
This method is a bit easier than Pushbullet because you can do it without logging into anything or installing an extension. The Google Now direction card is certainly convenient, but it doesn't appear reliably after looking up an address. The new search functionality has its niche when you think about it.
The new direction push interface has a drop down with all your active Android devices. It automatically defaults to your phone's location when the directions are sent, but you can search for any location in the provided box. It will automatically kick your phone into Maps so you can start navigation. I found the link went through almost instantly upon sending. It appears to be live for everyone (in the US) so check it out.