Matt and I are doing a little retouch of KDevelop's code completion. First, on Sunday, Matt made a change which prompts KDevelop to complete much more often than in the past. Before, KDevelop would only complete when it received a textChanged signal from KTextEditor and the current chars were "." or "->" or "::" ... Now, completions are computed for all chars that are not whitespace or empty.
Second, I just finished another tweak in how KDevelop handles c++ completion. In the past, KDevelop would not offer completions for methods in class declarations. I added completion for virtual method declarations. The completion is now queued with the 'virtual' keyword and offers a completion pop-up of all inherited virtual methods. When one is selected it inserts the entire declaration.
Overall it works pretty good, but there are a few bugs that present inopportune completions, but hopefully we can get those fixed soon. Make sure to check out the lastest bit and report any bugs you may find :)