Howdy. I buy typically direct or using PayPal.
Depends on what your needs are, as to determining which is the best.
For me:
Nisus Writer Pro (word processor)
Accordance (Bible study and analysis program)
Scrivener (writing and brainstorming app)
Notebook (planning, calendar, note keeping, etc.)
Keynote (presentation)
NeoOffice (allows interchange with MS Office apps)
Indesign (page layout) (I have the entire Master Collection)
Voila (screen capture)