Most of the problems I have had with the car came up in the first 15k of ownership, and I attribute some of this to this being the first year out of the new model. My advice is to skip this year, and buy a 2007 and up if you are set on a Grand Vitara.
The car is not a bad value overall, so I have mixed feelings about it. If you are a tall person over 6 feet and need leg room and head room, this truck deserves a look. Needless to say I will not be back for a newer version. It is just not a car that makes you excited to own it. There are highs and lows, and Suzuki in general seems to be aiming toward mediocre in their vehicle lineup.
Since I have the base model and 2wd, I find that the V6 engine is good, and I am never at a loss of power. This is my favorite facet of the truck. The handling is not bad for a small SUV. Gas mileage is not great around town, surprisingly bad actually, and the instant mileage readout on the dashboard is worthless.
Seat comfort is OK around town, but anything over 3 hours and you will be squirming. The biggest issue about the interior is the seat comfort. The plastics on the doors could be better, otherwise the interior is pleasant to look at and there is tons of front leg room.
Some design issues need to be addressed, such as the gas gauge being far off to the right, and not in your line of sight. Good thing they have a low gas light there! Also, the headlight setup takes getting used to. The headlights and indicator light are poorly done and you actually need to think about what "mode" you are in at night... The stock radio needs more power, the highway drowns it right out.
The truck seems to wear out tires much faster than normal which is a big problem as the tires are not inexpensive to replace. The dealer was not interested in talking about tires, although happy to do a rotation at a fee, which I agreed to do. I ended up replacing the tires soon after.