Kairo for Android is a theme pack for HD widgets that combines design elements from KitKat and iOS and Colorform. There's plenty of stylish preset colors to get you started. Once you've bought HD Widgets ($1) Kairo will enable you to bring the styles up to date, with a fully-fledged free version, and more extensive "XP" version costing a dollar.

The differences between the Kairo and Colorform theme packs are pretty subtle, so allow me to list a couple of them:

• Kairo widgets have rounded corners, unlike the square corners in Colorform;
• In Colorform you can add a tile and texture pattern to backgrounds. Kairo insists on the flat look.

The free version of Kairo also has more widget sizes available than the free version of Colorform. Free Kairo has a full screen widget and "tall" widgets, (1x2 and 1x4). The XP version of Kairo gives you more options like coloring individual clock parts and using a smart indicator (e.g. battery level) instead of the clock colon.

Compared to the standard HD Widgets theme (Glass Gems) these theme packs offer a more modern, minimalist design. Retro flip clocks are replaced with simple fonts that match the fonts in the latest Android versions. You can still choose photographic weather icons, but they actually look better with the minimalist ones. The interface of HD Widgets is so intuitive that you'll soon have something beautiful, and your device will have a completely unique look.

If you are keen to try out lots of different widget sizes, but don't want to pay the extra for an XP pack, Kairo will be a better option than Colorform. But both theme packs have great fully usable free versions, so if you have widgets you may as well try them both.