The notification area is pretty much stock android - it shows only notifications by default (below the top row, which is reserved for the time and date, plus two shortcuts). As of Android 4.2.2 Sense 5 also has toggles in the notification area, which you can access through a shortcut.
Another novelty courtesy of Android 4.2.2 is the widget lockscreen. It's disabled by default, you have to toggle it on from the Personalize menu. Unlike the stock implementation, you only get to pick a single widget, there are no multiple pages.
We didn't have time to run benchmarks, but in the time we used the One mini it felt smooth. The processing power available is slightly disappointing though - two Krait 300 CPU cores at 1.4GHz and only 1GB of RAM. The Adreno 305 GPU should be okay on 720p resolution, but the Samsung Galaxy S4 mini has a higher clocked chipset (1.7GHz, up 20%) and 1.5GB of RAM (50% more).
Before we wrap up the software overview, we'll cover the connectivity options of the HTC One mini. It packs all the basics - 2G, 3G with HSPA, LTE, Bluetooth 4.0 and Wi-Fi a/b/g/n and GPS+GLONASS. There are a couple of things missing though - there's no fast 802.11ac Wi-Fi or NFC. The MHL and USB host functionality has been removed from the USB port too.
The HTC One mini has an UltraPixel camera with Zoe very similar to what the regular One has. The one difference is the lack of Optical Image Stabilization. Other than that, you can do the same tricks with the One mini you can with the One.
The camera viewfinder fits perfectly on the 16:9 screen as that's the aspect ratio of the sensor too. There are two virtual shutter keys - one for photos and one for videos. A button on the other side of the screen toggles Zoe on and off.
Zoe is what enables the One mini to do many of its impressive tricks - like taking a burst shot and removing objects that have moved or making sure everyone in the photo is smiling. It also captures 3 seconds of video, which is later used to create 30 seconds of Video highlights.
Be aware that because of the extra information that the camera captures in Zoe mode, you use up a good deal storage with every shot, which is when you only have 12GB available (from the 16GB total). You can use one of the auto-upload services to back up your photos and free up some space - the One mini comes with 25GB of free Dropbox storage for 2 years. Another option to upload and share your photos is HTC Share, which also supports Video highlights.
The camera captures 4MP images and can record 1080p video, with HDR modes for both. You can also switch to the 1.6MP / 720p front-facing camera. You can also record 60fps videos (at 720p), which you can play back at different speeds for either HFR or slow-motion effects.
For low-light shots, the camera's LED flash has a feature called Smart Flash that adjust the power of the flash between 5 settings, depending on how close you are to what you're photographing.