My experience with 3M Cloud isn't as bad as yours, and it got somewhat better after they updated to the August 30 version. Still not ready for prime time, still not as good as Overdrive, which doesn't crash (though occasionally the server is down) and sends you a notice when a book is ready.
I discovered that you can get some access through the Web also:
http://ebook.3m.com/library/en/patrons/
Since it's on a browser, it's not as awkward and bug-prone as their own software. It lets me check out books, but not download them. (They show up in the regular cloud software, and they download there when you choose READ.) You can open multiple windows and do more than one search at a time. Sometimes it will make the regular Cloud software fail when you start it - I found that uninstalling and reinstalling the software fixes that. Sometimes it will also cause removal of the ebooks, so they reload when you open the regular software and try to read them. You're probably better off reading them in Adobe Digital Editions or with an ebook reader.
So, this stuff is still beta as far as I'm concerned, and it adds to 3M's reputation for producing less-than-professional software. For crying out loud, the Calibre freeware ebook reader for PC and MAc produces multiple updates in any given month!