The new Fortuner (Already released in Thailand, visit their Toyota website for better pics) is more of a face lift than an entirely new model. Dimensions are exactly the same but it's just a little lowered (nothing a change in rims could help). The biggest drawback is the retention of the current 2.7L Petrol and 3.0L Diesel Engines. However, fans of the Toyota brand and model could look for this as their replacement of their old fortuners.
The latest Montero Sport still looks the same. No face lift was done (except for the change in front grill on the GTV, w/c you can always buy separately). The biggest addition/change to the current model is the Engine. It now has VGT (Variable Geometry Turbocharger) on a 2.5 Diesel Engine. It has improved performance over the previous 3.0L Diesel Engine.
My take:
Wait for the official release of the Fortuner here in the Philippines if you're a Toyota/Fortuner fan. If not, then the latest Montero Sport is your best choice.
If you're a person more concerned on the cosmetic/external properties of a car, I think the new Fortuner is your best bet since it has a relative new face-lift which can turn a couple of heads. The current Montero Sport's image/form is too "pang-masa" already since it exactly looks the same since launch and since a lot are running around already (a lot could even an understatement for the commonness of this ride).
If you're a person more concerned on performance, go with the current Montero Sport w/ VGT, enough said.
