I'm running Lion, and I have had no wifi syncing issues whatsoever.
It is worth noting that my friend and I both use Windows. I don't know if that makes a difference, but I assume the code base for iTunes has some differences to account for the different APIs with each OS.
The two issues I've seen are:
1) iTunes complains that it cannot connect to a device. The device is not plugged in, and because of that, I assume WiFi is not connected. This makes the device inaccessible, so iTunes complains.
2) iTunes will constantly open itself if you have WiFi Sync and "Open iTunes when this device is connected" enabled. If you attempt to disable the automatic open, it has the potential to put your device in an unsyncable state. The only way to fix this is to tell iTunes to create it as a new iPhone, but unplug it before it can screw things up.
Yeah, that's a bummer. I can only assume it's a function of not having enough real estate on the iPhone to make it worthwhile. It works great on the iPad.
I've mentioned it before, but other browsers allow you to use tabs on the iPhone, and in my opinion, it works fine. They use the same browsing engine as Safari, so any speed increase in Safari
should affect the other browsers as well.