Usually, people who say q-jets suck are those who tried to tune one and don't know how. The q-jet can be difficult to rebuild and tune yourself, but a properly built and tuned Q-jet will run awesome! Not only for off roading, but there are many a drag racer who run Q-jets because of the power making capabilities of them. They have relatively small primaries and large secondaries. This makes for decent gas milage when putting around, and good power when you need it.
If you're looking for a quick cheap bolt on carb, you can probably find a better deal then a quality rebuilt Q-jet. But if you're looking for power, reliability, and off-road capability, I would definitely recommend a quadrajet.
Thomas.