In many circumstances chroot will improve security however a knowledgeable cracker will easily bypass it once root access is obtained. I believe that the latest version running on BSD is more secure.
There are many places that detail that chroot is not for security however they're buried in the mass of articles saying how it improves security of that particular organisation's application. Probably because they cannot be arsed to fix their security issues themselves lol.
As I understand it the tool was never designed to be a security tool so therefore it isn't. It would not surprise me if that is not changed soon due to the number of people using it as such.
Alan Cox, a major person in the Linux world, made the following comment...
"chroot is not and never has been a security tool. People have built things based upon the properties of chroot but extended (BSD jails, Linux vserver) but they are quite different."
It is likely that correct use of SE Linux would give much better security.