Although the colour theme is still dominated by black, its change is noticeable with the introduction of green and blue colours, and for the better too.
Most HTC built-in apps don't change much apart from the improved appearance, except for the Camera app. You can now switch between the front and rear cameras with a simple sideways swap. Previously this was buried under an obscure option requiring multiple taps to accomplish.
Overall this is a very nice update and we definitely recommend you to get it. As always, keep your phone charged while the update is in progress.