Everyone always talks about Truecrypt which is clearly most popular but both of the above are fully open-source. The latter is even part of the kernel. I'm curious what the appeal of Truecrypt is besides maybe portability (which is a pretty strong selling point).
The security assessment is for the Windows version of TrueCrypt only. Which also answers your question, TrueCrypt is appealing because it works on *nix, BSD, and Windows. It is also free and open source. The Windows version is easy to use, has a nice GUI and actually works as stated.
https://en.wikipedia.org/wiki/TrueCrypt#Licensing_and_Open_S...
Wikipedia lists it as "source-available".
TrueCrypt for example uses fixed and low pbkfd2 iteration counts as specified in the report.LUKS on the other hand uses adaptive pbkdf2 iteration count number that goes up automatically when a LUKS volume is created on a faster computer.
The appeal of TrueCrypt other than portability atleast among linux users is an easier to use GUI.Fortunately, there is a project called zuluCrypt[1] than supports TrueCrypt volumes among others and has a GUI window that is comparable to TrueCrypt's GUI.
If you are a user of tombs,zuluCrypt can also open tombs through its "gpg" and "tomb" plugins[2]
[1] http://code.google.com/p/zulucrypt/
The questionable license, and obscure nature of the project should be significant reasons not to use Truecrypt. That doesn't even begin to consider the actual security of the program.