With regards to my last post here, looking in the Squeezebox Server options there are some delay settings in the sync options. I increased one of them to 15ms from 0 which has slightly improved the issue of iPeng on the iTouch being a little out of sync. However its not perfect and when skipping through tracks it can become out of sync again but its better than what it was (I think).
Logitech Squeezebox Server – Settings.
It looks like they have based this new iOS playback feature using SqueezePlay. I did have SqueezePlay installed on my WHS initially and SqueezeSlave running on my other HTPC machine. I did not really notice any major sync issues then.
I then later uninstalled SqueezePlay on the WHS and installed SqueezeSlave instead as I wanted to run it as a service. Again with SqueezeSlave on both the WHS and HTPC boxes I have not noticed any major issues with sync. Only now using iPeng’s new playback feature has this become something of an issue. But for £2.99 to add an extra audio zone you can’t go to far wrong!
I renamed my iTouch here to iTouch – Kitchen
Changing this delay setting here affects if the iTouch is in sync or not with the other two SqueezeSlave players. However getting this value just right is tricky and I found when I thought I had it correct and all the players were pretty much in sync, but then skipping to the next track on the album the iTouch could come out of sync again. Some tracks start with everything in sync other tracks start and the iTouch is way out of sync. It still needs more investigation I think.
Overall I’d highly recommend iPeng if you have real Squeezeboxes or emulated ones like me. Its certainly the best app I have installed on my iTouch to date.
Update: Below is a response from the iPeng developer.
Syncing is currently not really supported. It can work but it's - as you have found - not reliably keeping sync. We're working on that.