Also when you go to the serpentine belt it reverses the direction of the waterpump- this is where the whole - balanced flow water pump & system comes into play.
There are people who get long life out of the serpentine belt, some with short lives- basically the same as V belts. Good and bad with both.
Personally I always liked the v belts- I really like it because you can easily swap to the hmmwv fan clutch and have control of when the fan is engaged or disengaged.
Not as crucial with square body as the gmt400 or hummer use.