I hope it replaces the notoriously hard to use gdb. I actually like doing things on the commandline and am used to using minimalistic tools like vim, but gdb's obscure commandline behavior makes it very hard for me to use it for any real project.
I am on 6.8.50.20081120-cvs I seem to have auto completion (on tab)
I've seen this since about 6.7, I last used 7.1.