There are some great new features in the latest version for iOS including:

• Quick Selection Tool – this is an awesome and super accurate new selection tool that lets you swipe over areas to select them.
• Magnetic Selection Tool – this tool snaps precise selections around objects and is really fun to use.
• Selection improvements – there’s also a ton of improvements to the overall selection experience (including an Invert Selection feature).

I use Pixelmator as my only image editor and love it.