HEROLINT  PDFPenPro does some nice things, but there are too many deal breakers.

First, when you try to center text in a text field, the size of the text field will grow to the length of a football field. There is a work around for this, but it shouldn't happen in the first place.

Second, the grid doesn't work right. If you place an object on the screen when the snap-to-grid feature is turned on, it lines up right, but if you lay something out without snap-to-grid, and then turn the grid on, instead of aligning the corner of the object and the corner of the grid, it will align to wherever the grid intersected the object when you turned snap-to-grid on. The only way to fix this is to delete the object and recreate it.

Third, the snap-to-grid functionality is not granular enough, making complex page layouts a huge pain in the butt.

There are some other issues too, but these were the main ones.

I like one of the company's other products quite a bit, Text Expander, but I do not recommend this one unless you are planning to do some extremely basic documents with it that contain editable fields. Otherwise, just print to PDF. It's cheaper.  
(Version 3.4)