Not sure where you heard Sync is not very good, as I have it in my '10 Ltd and like it alot! This is compared to the navigation in a couple different German cars, two different Japanese cars and two different garmin's. Granted both German car's were older technology... one was an '05, one an '06 and the problem I have found with garmin's is that they will ultimately get you to you destination, but it may be after a few unnecessary turns or streets.
The Sync navigation is better than that of a toyota, or lexus (although probably the same guts in those two cars)... I have found the graphics to be state of the art, with the 3D or "eagle eye" earning the most praise from those riding with me. The turn-by-turn aspect is even more impressive, with a split screen view that counts down from a mile and then a 1/4mi. It seems to get me there everytime, and seemingly without any unnecessary roads. But again, I guess I'm not sure about that last part.
The most important thing to me in navigation in a car these days is that it is integrated into the dash, in fact, I've even retro-fitted into my wife's last car and another car I have. I just cannot stand things stuck to the windshield. Also, with an '11 Sync system, they have made continued updates/ improvements to it since introduction and it was pretty impressive then. So, there you go.... good luck.
