Most Forum members report that GoodReader, the 'Swiss Army Knife' for the iPad, is the best PDF reader for large documents. I've not read one as large as you are proposing - but 300 pages is certainly no problem. I'm sure other Forum members will be able to report on this as GoodReader is consistently voted the No.1 'Must Have' app for the iPad. There seems to be some uncertainty as to whether the iPad2 has the same or twice the memory (RAM) as the iPad1 - which, I guess, would impact its ability to read really large documents. We all know that the iPad2 has a greater CPU performance and a significantly better graphics performance than its predecessor but whether the current edition of GoodReader can take advantage of that is, at best, uncertain.
1200 pages!! That *is* a big document!!
Tim
Scotland