These are 2 completely different types of cars.

The Hummer H3 is a relatively slow, but tough 4WD, which will certainly hold up well in an accident, and will be able to cross the dunes with no real issues. (Although the engine is a little underpowered)

The SRT8 is a 420bhp performance 4WD, which is very safe, but will never go off road. Its a handful to drive if you are not used to such power, as it will out accelerate a lot of cars here in Qatar.

The Hummer is a lot cheaper to run in terms of fuel etc. The SRT8 is a 6.1 V8 which drinks gas, and the parts are hard to get hold of, and they are expensive!

However, put your foot down in the Jeep, and you forget all the negatives!