Skim - Potential OS X PDF Editor (Open Source)

Looking around for a PDF viewer that lets me annotate the document and doesn't suck, I ran into Skim, an open source PDF viewer and annotator for OS X. It has some obvious shortcomings (such as not being able to edit text), but it's ahead of all other contestants.

I wish it could but it can't...

• ... edit the document text
• ... export annotations such that other PDF viewers can see them

However, it...

• Underlines
• Highlights
• Strikes-through
  

And, like Preview...

• ... makes red ovals
  
  
  
  
  
• ... creates blaring yellow comment boxes
  
  
  
  

And, somewhat unnecessarily...

• ... Green Boxes!
  
  
  
  
  
  
  
  
  
  
• ... Icon notes! (Text appears if you double click)
  
  
  
  
  
  

The verdict

Better armored than Preview, but also more cluttered. Clearly the best alternative so far - however, no cigar. It seems to me like someone could make a name for himself cracking this nut. Takers...?

Full screenshot