People who are in love and are loved back will probably tell you that Love is Best thing in this world! They feel elated, like they can defy gravity and like they can take on the world.
People who are in love tend to feel healthier and have more energy, so most of these people would say that Love Is GOOD.
You should take care not to confuse Love with Obsession, although the two can feel very similar, it is often when these two are confused that Love is BAD
If you love someone you should accept the whole of them and not expect them to change too much. Often, people fall in love with a person, but don't like certain elements of them, either their habits or their family, and try to get them to change. To begin with what might seem like mild jealousy, can escalate and in some extreme cases this can become severe bullying or abuse. In these instances, people would definitely describe love as being bad, although one could argue that this is not the definition real love. If we take that to be the case, then true, real, all accepting love must be good :)