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 
very good !!!
good news for kde developers