My favorite feature upon initially opening PhotoPlus is the How To toolbar, which gives you a long list of tips on everything from how to get started to photo retouching to creative effects. If you need additional help, the Help search is also very complete.
PhotoPlus X5 makes it very easy to make adjustments to levels, color balance, vibrance and a multitude of other details using a pick-and-click method. Every change you make to your image is stored in a new PhotoPlus layer automatically. In this regard, PhotoPlus X5 is a lot like CameraBag2 ($29), and it's very cool to be able to make major changes quickly. You can also use PhotoPlus to create Macros of effects and apply them to a batch of images. Unlike CameraBag2 however, creating macros and applying them to a batch is for advanced PhotoPlus users or those with a lot of patience.
Adding and removing parts of your images in PhotoPlus is as complex as you need it to be. PhotoPlus has a built in Cutout Studio, which takes you step by step through the process of isolating part of your image. But more experienced users can achieve the same effects using layers, the magic wand, and lasso tools, as you would with Photoshop or GIMP.
PhotoPlus includes a very nifty, simple red-eye remover, which works the same as (also $90). I much prefer the default in PhotoPlus for this, which draws the patch over the eye from the edge, rather than the middle (Xara). However, the result seemed more natural in Xara Photo & Graphic Designer, and more obviously a patch in PhotoPlus.
I found the tools in PhotoPlus more complex than Xara Photo & Graphic Designer 7, and more likely to not work as you expect. In addition, Xara offers vector-based drawing tools within Photo & Graphic Designer, whereas PhotoPlus is purely raster: just like with Adobe Creative Suite, you need sister program DrawPlus (an Adobe Illustrator clone) to add vector components.