"Worth it" will vary person to person, but IMO the 8" display makes the interior. It looks kinda cheap without it. Not to mention that a simple hack truly turns it into a mobile infotainment system. Put me down for a YES!
By brother has a '10 V6 Premium without it and I second this. I do have it in my '10 GT and wouldn't have it any other way. It does really tie the interior together. Besides, it's a cool toy with lots of features.
A nav unit has things that are really difficult to add later on using the aftermarket. Personally I like tech and creature comforts. If you find you want those things later on you're basically SOL until you sell your car which would really impact the enjoyability (if that's even a word!).
NoVA just means Northern Virginia VMP Tuned Roush•79mm Pulley•ID1000 injectors & JLT Intake•GT500 Axlebacks•UMI Panhard Bar, LCAs, & UCAs Steeda Ultralite Springs•Koni STR.Ts•19x11 Gloss Gunmetal Forgestar CF10s •2012 GT Premium 401A Black&Brick