We use EasyQlik QViewer for opening QVD files. There is a physical limit to the number of records that can be opened. It depends on the number of columns, but I have opened 5 million rows for viewing. There is also a very limited query tool that will let you count records and find specific rows quickly. You can find it easy enough on a google search and the unlicensed version will let you search up to 50000 records
Other than Qlik, I have not needed to open QVW files for anything else.
