Alrighty here we go...
Advantages:
The two houses are balanced as one has a set number, and another depends on the population of their state. This creates a Balance...
There must be a 2/3 vote from either of the houses for something to succeed. So a process may be slower, however, more safe.
Disadvantages:
Many people can be voted into these positions. TO take over a certain house.
Sometimes the houses can be severely divided. Such as Republicans having the Senate. And the Liberals the Representatives.