The choice between a Toyota Prado J90 and a Toyota Surf is not an easy one. It mostly boils down to the predominant use intended for the vehicle.
The Prado seats seven, the Surf seats five. On the other hand, the Prado is a wallowy, roly-poly boat-like jumble in its driving dynamics while the Surf handles almost car-like with little body roll owing to the use of independent front suspension and the X-REAS diagonal damper linkage by use of hydraulic hoses and a mechanical centre valve.
The use of IFS in the Surf may be its undoing too; in off-road jumps, there is a tendency to break the front axle, causing the vehicle to bury its nose in the dirt like a fatigued camel.
A Prado will take those jumps and more, and just keep going. The weak IFS issue also affects the 100 Series Landcruiser VX too, by the way.
In a nutshell, if you have many passengers and engage in wild 4×4 antics, get a Prado. If you drive mostly on-road and slowly off-road in not-so-extreme arenas, get the Surf. Also, the Surf is generally cheaper than a Prado in the used car market.
The best engine is the 3.4 V6. It is the most powerful, it is very responsive and one can install a TRD supercharger with no difficulty at all.
The Paji’s orange Prado that impressed me so much packs this engine (without the blower, though). Second best and the ideal alternative would be the 1KZ. A robust, durable powerplant, it delivers both torque and economy on a scale atypical of most SUVs.
This engine almost has no issues at all, except for a few isolated cases of turbo failure following poor use by drivers. Properly driven, it will run forever.
The D4D is the most advanced of the three, and is thus the most economical. It is a lot smoother than the 1KZ, delivers more power but is quite complicated and thus prone to having issues, particularly with injectors. Its construction also makes disassembly a real pain for the inexperienced grease monkey.
My choice would be the 3.4 (I have clocked 180km/h easily in one, hitting the fuel cut-off point; and I wasn’t even anywhere near the red line).
The frugal mentalist’s choice would be the 1KZ. Those that buy iPhones and Samsung Galaxy handsets within a few hours of a new model being launched are more likely to go for the D4D. Go figure.