I don't have a 10" Android-based tablet but the iPad 2 + GoodReader works great for PDF. Easy access to the folder/file structure is shot, but GoodReader has various methods available for syncing. The iPad 2 also has amazing battery life. The advertised 10 hours isn't a lie. I'd say for what you want, the iPad is a safe (but expensive) choice.
I've got a 7" Nook Color running CM7 and the screen size/resolution just isn't big/high enough for my reference materials in PDF (lots of charts, diagrams and formulae).
I think the big thing here is finding what apps are available for Android. Even if you can't test it yourself, if you can find at least one app with good reviews that does the things you need it to do, you can then go researching what hardware would work best for you and your budget.
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