What are some benefits and drawback of stratified sampling?

There are a number of benefits and drawbacks to stratified sampling. Two benefits are:

• You have a cross-section of the population, so this is more likely to be representative and thus easier to generalise.
• You are less likely to get a "freak" sample.

Two drawbacks are:

• This is a very long and difficult form of sampling. It could be inconvenient or costly.
• You may not stratify the population by the relevant factors - what if their gender isn't important, but their economic bracket is?