The iPhone 6s and 6s Plus have been released, and Apple says it sold more than 13 million of them worldwide in the first weekend of availability. That’s a lot of phones–and if you already have one, congratulations!

If you’re still thinking about whether or not to upgrade, here are some general impressions of the new phone to help you decide.

The iPhone 6s and 6s Plus look nearly identical from the outside. The new phones are slightly heavier than the old models, and almost imperceptibly thicker. Still, most existing cases should fit just fine. However, there are a lot of internal changes, many of which are focused on speed.

Touch ID, the fingerprint sensor that debuted on the iPhone 5s two years ago, is incredibly fast now. Some users even think that it’s too fast. For example, if you like to tap the home button to get a glance at your pending notifications without unlocking your phone, you can’t do that anymore. It’s that quick. So, you need to either press the power button on the side or use a non-Touch ID-enabled finger (or even a fingernail) on the home button.

Apps load faster too, thanks to the new A9 processor and increase to 2 GB of RAM. Power users will especially appreciate it, because Safari used to crash and reload large pages (especially longform articles), but that will likely be fixed with the new phone.

I use “Hey Siri” all the time. It allows you to turn Siri on simply by saying the words “Hey Siri.” On previous iPhones and iPads, the device needed to be plugged in for the feature to work to avoid draining the battery by having it listen all the time. Now, the iPhone 6s can listen for the magic words without draining the battery. It’s very convenient (and something some Android phones have had for quite a while) to just talk to Siri in the car or across the room without needing to pick up the phone. “Hey Siri, what’s the weather today?”

The new 3D Touch feature, a more advanced version of the Force Touch in the Apple Watch, is great for power users and will become even more useful once developers really figure out what it’s used for and how to enable it. Give it a few months. There’s also a new vibration engine that provides “Taptic” feedback alongside the new 3D Touch feature, but it also smooths out the vibrations when alerts or calls are received.

There are nice improvements to the camera in the new phone, but they’re really only apparent when you take photos side-by-side. Still, it’s likely the best camera that most non-photographers have ever owned and, like the old saying goes, the best camera is the one you have with you–and since this camera will be carried around quite a lot, users will get a lot of great shots. The iPhone 6s Plus now adds optical image stabilization to videos as well as photos, which is a nice improvement for those using the new 4K camera mode.

Speaking of cameras, some users think the Harry Potter-esque “Live Photos” feature is more of a gimmick–but, depending on the photo, it can deliver something really special. Rumor has it that a future version of iOS 9 will automatically disable the feature if you move the phone quickly (like if you tilt it downward after taking a picture), to avoid Live Photo video of the floor.

The iPhone 6s Plus also seems to be more difficult to bend than earlier generation iPhones, which should be really good news for concerned buyers.

At the end of the day, if you get a new iPhone every year, you’ll like the upgrade. If you have anything like the iPhone 5s or older, it’s almost certainly worth it–if for nothing else than the larger screen, which is really, really nice.

Do you have your new iPhone 6s or 6s Plus? Let us know your impressions in the comments below.