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Fortunately most of my drawings will be in PDF format. I suppose I can set up a DropBox account to keep my files up to date (plenty of revisions issued). Other than iAnnotate, is there any other annotation software worthwhile to make notes on the drawings? I'm also currently debating between the Otterbox Defender and the Incipio Destroyer.

I greatly appreciate everyones input. I understand the iPad is a "consumption" device, but for my tasks, I think it'll work just fine.

Check out readdledocs for storing and viewing PDFs. You can highlight text and take notes.
 
For a second I thought your iPad is in construction.

iPad to be used in construction job=otterbox defender
 
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