I have a Sandisk Cruzer Blade 4Gb USB stick with Sandisk Secure Access Manager on it.
This operates satisfactorily and appears to leave no insecure trace of a file that has been opened read-only after it has been closed. The software also offers the use of secure space on Yuuwaa.com as a backup, which in principle is very useful and is very easy to operate. However, what is not made clear is that when opening files from Yuuwaa.com, temporary files are created which are not deleted when they are closed. Thus if e.g. you go into an internet cafe on the other side of the world, access a file from your vault on Yuuwaa.com , a copy of that file will be left on the PC you have been using, which is potentially highly compromising if you open a file containing sensitive information. My experience of my old CruzerLock was that most public/institutional PCs would not allow it to operate because it involved installing software, which I assume will be the same for Sandisk Secure Access Manager on a USB drive, tempting one to use Yuuwaa.com in that sort of situation where you have online access, which is potentially compromising.