1.5 is great for me !
Faster to start, the possibility to browse faster with the nav button (in Library, in books, in Lookup mode, even in menus !), be able to change rapidly the size of font with the buttons in the right side, and of course Folders view... All great points !
The only problem was with the dictionaries and the delay of the search, as it seems now that it scans through all the subfolders.
Problem solved with Folder view and the folders/subfolders/ebooks in an folder parallel to eBooks folder, and only the dictionaries in eBooks. (Thanks Chlorine for the idea !)