Very few things are complete in this world, so in that sense you are correct... Still, I hope you've given Syncevolution a chance lately before lumping it in that group of "non-complete" projects. Patrick & team has done a very good job on it.
I'm sure I'm biased from having written the MeeGo netbook UI for it but from where I'm looking, Syncevolution is not only the product that actually works very well right now, it's also the one that has most potential in the future. The feature list is fairly impressive already, extension capabilities have been proven and development is in good hands.
In short: while you wait for Opensync 0.40, remember to check out Syncevolution.