There’s no question Apple’s iPhone 6 and iPhone 6 Plus are popular among consumers. In addition to breaking records stateside, both devices have allegedly been a hot item overseas, too. That could equate to some incredible sales next quarter—people are still lining up for the device, which goes to show just how incredible reception has been so far.

Apple still hasn’t provided a breakdown telling us which of its new phones is the more popular version, though the iPhone 6 Plus has definitely been more difficult to find; whether that’s an indication of popularity or lack of supply is unclear. Either way, there are some clear differences between the two, so making a decision shouldn’t be all that hard when push comes to shove.

If you’re upgrading from an iOS device that’s a few years old, however, upgrading to the iPhone 6 is a no-brainer. You get the benefit of Touch ID, the faster A8 chip, a sleek design, and an improved camera. Oh, and a 4.7-inch screen, which sits around that sweet spot in size. But what if you’re coming from the iPhone 5s, which is still a very capable and very handsome device in and of itself? That’s a tougher decision, and one Mark will answer in the video above.

From a spec standpoint, the two aren’t significantly different. Sure, the screen of the iPhone 6 is obviously larger, but elsewhere they are very similar. There isn’t a huge difference in battery life, while the iPhone 5s still takes some terrific pictures thanks to its 8-megapixel sensor. And because of optimizations made in iOS 8, you won’t really notice a huge difference in performance.

It’ll be a hard decision for iPhone 5s owners; the jump to a 4.7-inch screen alone might be worth the upgrade, but otherwise there’s not much there to warrant spending another few hundred dollars. Mark expounds on the debate much further, so check out his video to see what he thinks about the two devices.