The addition of a presentation tool isn't why I had to be so enthusiastic. In fact I still prefer Thumbstacks. What I really find useful is the addition of folders so that I can finally organise what was becoming a huge list. Sharing items with people is now a dream. Write some notes in class and then e-mail them to a group. Charts in spreadsheets too and several other tweaks regular users will appreciate.
Read all about them here.