It changed my default multiple times as well, which is a real nuisance. My initial reactions are that it is the fastest pdf viewer I have, but if I am viewing a lengthy document, it wants me to page through all the pages to get to the page I want. I expect to be able to indicate which page I want to jump to, and have that occur, e.g., I should be able to get to page 236 of a 400 page document without paging through the first 235 pages, and I didn’t find a way to do that with this software. In addition, I realize now – but didn’t prior to downloading and installing – that it is the standard version. If you want to introduce a new player into the crowded pdf landscape, you need to showcase ALL that it can do in the time-limited versions you are offering. All that I could do, other than viewing and paging through multiple pages, was highlight and split the document. Presumably you need to have the pro version to do more. I already have Adobe Acrobat, Nuance PDF Converter Professional, Finereader, Omnipage, and various other editors/viewers that do as much, and often more, than this software does and do it in an easier, or at least a more intuitive manner, than this software. Perhaps I should only compare it to Acrobat’s “little brother” types of software, the ones that cost less than $50. I have a lot of those, too. While this software says it does things that the “little brothers” can’t, to stand out as a newcomer in the crowded pdf field, they need to showcase the advanced features, and those features need to work well. Just a suggestion . . . .