I havent had any errors like that, but it does seem a little slow to me. It seems to react slowly to turns, much slower than TeleNav. the interface is very "pretty" with blues and yellows, but seems abit too much for a commercial app if you ask me. (Very similar to what VZNav did). Overall not bad for 6mo free but still a bit behind TeleNav.
I will add to my review a bit later