Using Tablets for Navigation, Sure. Its a good idea. But if you own a smartphone, you can do it on that too. But YES, i do agree that this solution will be hell of a lot better than the Navigation system we get in Cars (that Tom Tom or Garmin etc)
Now, talking about Sygic, hate it all you want. But don't neglect the fact that Sygic is the ONLY company truly supporting Pakistan, and i believe Sygic maps are as detailed as Google Maps (NOW) ... and now they are going to get even better. SYGIC is Current THE BEST Offline Navigation option we guys have, here. So make sure you SUPPORT THEM by BUYING their app. (Their PK dept recently have been experience some financial difficulties and if we continue to pirate their app, i am afraid they might drop support for Pakistan ... which would be the worst thing to happen)
If someone believes that paying $18 on Sygic is a "waste" then he is free to look for other choices which support Pakistan Officially, Release frequent Maps Updates and the best part, does Offline Navigation. I'll be happy to listen to the counter argument from these people.
Talking about Accuracy of Navigation, it has never been very accurate. Not even your beloved Google Maps, which, not to forget, dont' even work Online (please, don't use that "Offline Cache" system in your argument. That is of no use when we can't use Offline Navigation, which still asks for an active data connection --- I do understand the reasons behind it though, that Google wants to have more accurate navigation experience ... but that doesn't work in Pakistan)