Ive thought a lot about them, personally I would go with a bigger offset wheel, not as much stress on the axels and drive train, though for a total offroader I wouldnt see any problems with them, but again the cost of good spacers to the cost of a set of steel wheels can be the same.
I got this just from bigger offset wheels

There have been issues with failing wheel studs and stub axels but they could be low quality spacers and studs, but my money would always be on the wheels, you pays ya money you makes your choice.