Find access from a friend or go to Incredible connection or Games or some store that allows you to play around with the tablets and send a sample file by bluetooth. The standard 1280x800 resolution is not great ( for me anyway) as it needs a bit of zooming and panning to view comfortably. The more recent Note and Pro range will be much better (and dearer) than the standard Samsung Galaxy Tabs.
I took a plunge and bought a Ramos i9 from a Chinese site (banggood.com) and loaded it with PDF magazines and books. My old 7" Samsung is now very unloved, I have hardly used it since. Spent R2500 with shipping and customs on this device... and although not perfect (features missing like GPS, Google Apps) it does a great job as a PDF viewer with SmartQ Reader app. I am not bothering customizing or rooting it, nor waiting for updates or custom roms - it's job is to be a PDF viewer. I told myself if I was to regret the purchase in 4-6 months time I could be buying a brand name tablet that could be R2000 cheaper.
The other great deal was the LG Gpad 8.3" that was going for R2700 a couple of weeks ago - although I don't find them locally right now at the usual suspects.
Those that have the courage to gamble on a Chinese tablet should check out this blog
http://mikecanex.wordpress.com/ where the author is on a similar mission to find a tablet for reading PDFs.