As usual, not every single function of the phone is working (camera, USB tethering etc) but there are quite a number of things that do work i.e. WiFi, SMS, GPS, Sound, Calling, Touchscreen, Stable 3G, Gmail sync + calendar, SD read/write, all sensors, Bluetooth, Hardware acceleration, WiFi tether, Market with paid apps and more so it’s safe to say you can use it as a daily phone (assuming you have no use for the camera or USB tethering).
Judging by the video demonstration, it’s safe to say Ice Cream Sandwich can run pretty well on this 21 month old phone. Sure it’s not as smooth as the Galaxy Nexus, but this definitely gives hope to all the other Android users out there without dual-core phones and looking forward to having Ice Cream Sandwich on their devices. Now, if only phone manufacturers would spend as much effort as the developer community when it comes to updates. Head over to XDA-developers if you’re keen on flashing this custom ROM to your HTC Desire.