As a regular user of both Firefox and Chrome, I can say with some certainty that, where most features are concerned, the two browsers are neck-and-neck.
Sync, however, is not one of those features. Chrome sync works as it shoud, with speed, simplicity, and what I like to call get-out-of-my-way-ness. Firefox Sync is another story. It's a headache to set up, and once it is, the sync works intermittently at best.
If you want to quickly send a tab from your desktop to a device, though, a simple, lightweight extension can help. The appropriately-named Send Tab to Device does what it says on the tin. Install it (no restart required, but I am assuming you have Firefox Sync already set up), and when you get to a page you want to send to your tablet or phone, just right-click anywhere on the page to open the context menu. You'll see the option near the bottom of the menu. Click it, and Firefox will ask where you want to send the tab (you can choose any single device that's set up with Sync, or send it to every device with which it's set up). Click 'ok,' and you're finished.
The results aren't immediate (it's piggybacking off of Firefox Sync, after all), but it is pretty fast. Your device will show a notification in Android's notification menu. Tap it to open the page in Firefox. Simple.
Until Firefox Sync does what it should do adequately, this addon is simple and light enough to be a no-brainer for Firefox users.