You CAN have problems with spacers. If you ignore them, buy cheap ones, get spacers that just sandwich between the wheel and the wheel mounting surface, you will have problems.
If your diligent about maintenance and don't buy cheap ones, they can be trouble free too. You need to get the ones that bolt to the factory studs, then have another set of studs to bolt the wheel to. You need to check lug torque often until you get familiar with them. Not just the wheels, but the spacers too. That means you have to pull the wheels off more often. But...I've been running spacers (adapters, actually) for four years and I've not had ANY problems whatsoever.
Its all about understanding what your doing and how to take care of the issues.