This might help someone else. I was originally having problems synching with my iPad. I could see the ‘sync’ folder, the firewall was off, etc.
I posited that the wireless connection which is shared in my building might have something to do with this. My suspicions were increased when I couldn’t synch 1Password. Today I picked up a VirginMobile mifi network and connected my Macbook and iPad to that. It worked like a charm. DTTG is now up and running.
Except I do not want any cloud based backup or sync. For me security means I need to be in total control of my sync and data which Dropbox, Mobile Me etc do not allow. In fact the cloud problem is why I am even looking at DEVONThink.
I want to move away from Evernote, which has been a stopgap for mobile notes for me. I’ve had to limit what notes I can carry due to security reasons. DTTG with local Bonjour sync will allow me to again carry all my various notes in a nice secure format on my iPod Touch.
Me, too. Although I’m not as concerned about security as you are (I am a little), my problem with the cloud is that I’m often without a WiFi connection (I have an iPod Touch and an iPad without 3G). Evernote and Dropbox don’t work very well without internet access. I’m aware of the “favorites” feature of these apps, where you’re supposed to be able to store some documents locally, but I’ve had that feature fail on me once for both apps. After that, I never really trusted them again.
That’s why I used Evernote, but no matter what - whenever it was “important” that I be able to grab some information it would fail on me. I do not know why, but it would… Which is why I switched to DT and DTTG.
I live in a very rural area, and much of what I need to access as notes are things that I need when outside in the fields looking at sheep, no wifi at all anywhere nearby. I have an Evernote Premium Account, that allows me to have all my notebooks offline and on my iPod. So that is an option for no internet access.
Just be willing to reinstall and re-download all your stuff regularly. I usually have to reload everything from scratch about every week or so due to bugs/issues. It takes about 4 hours to download all my notes when I have to do this.
I’m hoping DTTG with sync of only changed notes will not be as problematic, if we can ever get it working at all 
As mentioned previously, we have two problems we are working to resolve for people who simply are not seeing Sync groups in the desktop product or who cannot ‘see’ their desktop machine from DTTG. We are also noting that there are people who do see Sync groups and do see their Mac in DTTG, but syncing just seems to fail. These issues are due to a variety of network-related matters, and users who have solved these issues are finding that “one size does not fit all”. The next update of DTTG will have more robust networking and Bonjour functionality, but my experience with networking tells me that this alone will not resolve everyone’s problems. While we are considering another approach that will improve the user experience (and robustness) of WiFi syncing, we ultimately cannot resolve problems due to specific routers and router configurations. That said, this is a learning curve for us as well and we will share whatever information comes to light in order to assist our customers in making this work seamlessly in as many situations as possible.
Is there a specific port or ports that need to be opened for the sync to work on wifi?