Electromagnetic compatibility has NOTHING to do with whether your dimmer and bulb are compatible… it has to do with your electronics emitting signals that mess with radios and TVs).
Some bulbs are not dimmable (very few CFLs are, maybe half the LED bulbs are). Some dimmers will only work with incandescent bulbs or require a certain minimum load to work.
I have over 300 bulbs in my house (My adventures in LED home lighting) , all LEDs, almost all on dimmers, almost all bought from a company that re-sells returned items from places like Home Depot (at less than 20% of retail prices). I suspect that most were returned because of dimmer compatibility issues.