HTC must have a team of developers locked up somewhere underground and only given meals when they get things right. If that has even distant connection to the reality, they must've been treated to a feast upon completion of the Hero user interface project.
It used to be just TouchFLO, but enter Sense UI. Simply put, Sense UI is a cross between TouchFLO and the stock Android interface, but at the same time, it's neither of those. Some changes are purely ornamental, while others profoundly affect the way you work with you mobile phone.
The arrow button at the bottom of the screen that used to pull the main menu up is now replaced with three virtual keys and an arched scrollbar. The left key launches the main menu (this time around, you simply tap - you can't drag the Main Menu out, though you can drag it back in). The middle key is a shortcut to the Phone app and the right key brings up the "Add to Home" menu. And there's plenty to add to the homescreen but more on that later.
The scrollbar at the bottom is just an indication of which homescreen is on - it can't be used for actual scrolling. HTC have extended the homescreen to seven partitions instead of the usual three. Even if it sounds too much, with all those widgets (which are quite useful too) it may not even be enough.
One of the most important novelties is the addition of scenes, which are essentially six custom desktop setups (Work, Travel, Social, etc). Each scene changes the wallpaper and the widgets on the homescreen - for instance, the Work scene has a stocks widget, while the Social offers a Twitter widget.
You can't modify the scenes but if you rearrange the current homescreen you are prompted to save changes as a new scene. The Clean slate scene in turn lets you start from scratch - it's just the default Android setup with a Clock and a few shortcuts underneath. Switching between scenes takes a couple of seconds but sure allows wide customization - the business and personal mode that other phones offer seems quite a limited solution compared to scenes.
Scenes are far from perfect though: the Travel scene has the HTC Footprints widget but nothing on GPS or maps. Unfortunately, you cannot edit the default scenes. Your only option is to save a new modified Travel scene under a different name along with the original.
Changes to the UI that Sense brings go deeper than just the homescreen. For example, the main menu has the typical icon grid layout, but you can switch it to a list similar to what you see in TouchFLO. With it, you can use kinetic scrolling or an alphabet scroll, which makes locating apps faster.
When adding a widget to the homescreen you are faced with two options - Android widgets (the stock widgets) and HTC widgets. HTC are obviously quite proud of what they've achieved and with good reason. A neat HTC solution is the Settings widgets - simple switches that turn things like Wi-Fi, GPS and Bluetooth on and off.
When you select a widget you are prompted to choose between several versions - most widgets have at least two styles. The different versions typically offer at least two sizes of the widget, different look (There are twelve different clocks. That's right, twelve!) and some even offer different functionality.
Take the Twitter widget for instance - one version also shows updates for the people you follow, while the other version only lets you tweet from the homescreen. There's nothing stopping you from using both.
The HTC widgets offer a better level of interaction than the stock widgets - there's a Favorites widget that keeps a list of your favorite contacts you can scroll through, no need to get to the contacts list.
The Photo album widget is a "stack" of photos that shows all the photos in some folder and you can flick them to view the next photo in line. This is quite fun but the experience is somewhat ruined by optimization - during the animation of the photo going up and the next one settling in, the widget uses low resolution previews of the photos and it takes a couple of seconds for the next image to fully load. Larger photos suffer the most from this.
The Messages and Mail widgets work much the same way, but instead of photos, you flick messages. And you don't get the pixilation issue.
The way widgets are moved around on the homescreen has changed too. A green rectangle marks the area the widget will occupy while the rest of the background is faded. If the current section of the homescreen is full, a message urges you to move the widget to another section.
The UI is generally fast but at times it would become frustratingly slow. Like when you access a microSD card with a lot of image folders. It's not that it takes a while to open the folder, but the couple of seconds lag before the Hero would continue registering taps that is so disappointing - a "Loading…" sign is better than a frozen screen with no indication of what's going on.
Some of the Sense solutions are not as positive - on the homescreen the trackball is only good for scrolling desktops, you no longer can select anything with it. Tapping a shortcut is of course faster than selecting it with the trackball but this change is a little limiting.
Two more things - most apps won't run without a microSD card inserted and screen vibration feedback works on the virtual QWERTY keyboard but not elsewhere throughout the homescreen.
And just wait to see what they've done with the phonebook.