No difference other than the extra tabs we add in KdePrint::createPrintDialog() that add the CUPS options like n-up, banner pages, job options, etc, and the new hacks in 4.4 for odd/even pages and server-side page selection via CUPS. Where-as in QPrintPreview if you click on the 'Print' button you get the 'pure' Qt dialog without the tabs and extra options. Try File/Print directly in KWord versus File/Print Preview then Print to see.
KPrintPreview is ugly, it just silently prints to PDF and then calls the KPart, so is very limited in that respect.
I plan to submit a merge request in January to add the advanced page range stuff into Qt 4.7, and in Feb merge the CUPS options and file printing, so hopefully in KDE 4.5 the issue will be moot and we can migrate to QPrintPreview. See http://qt.gitorious.org/~odysseus/qt/odysseus-clone/commits/advanced-page-selection. But each app will still need to add the print preview slot as QPrintDialog doesn't have a 'Preview' button (well not yet anyway :-) ) so it's not a lost effort if done in the 4.4 timeframe, it just makes it easer to find where to do the migration.
No difference other than
No difference other than the extra tabs we add in KdePrint::createPrintDialog() that add the CUPS options like n-up, banner pages, job options, etc, and the new hacks in 4.4 for odd/even pages and server-side page selection via CUPS. Where-as in QPrintPreview if you click on the 'Print' button you get the 'pure' Qt dialog without the tabs and extra options. Try File/Print directly in KWord versus File/Print Preview then Print to see.
KPrintPreview is ugly, it just silently prints to PDF and then calls the KPart, so is very limited in that respect.
I plan to submit a merge request in January to add the advanced page range stuff into Qt 4.7, and in Feb merge the CUPS options and file printing, so hopefully in KDE 4.5 the issue will be moot and we can migrate to QPrintPreview. See http://qt.gitorious.org/~odysseus/qt/odysseus-clone/commits/advanced-page-selection. But each app will still need to add the print preview slot as QPrintDialog doesn't have a 'Preview' button (well not yet anyway :-) ) so it's not a lost effort if done in the 4.4 timeframe, it just makes it easer to find where to do the migration.