I'm strongly against programs or services which 'make' websites for you. My experience with them is that the code they produce is simply awkward. Some can produce W3 valid code, but that doesn't necessarily make the code great. No matter how wild the claims are, I still don't trust them.
abduraooft is correct. The only way to do it properly in my opinion is to code it yourself. Dreamweaver is fine as long as you keep an eye on the code. If you are not involved with it, and a program generates it for you; modifying and changing it will be much more difficult, adding to the disadvantages. If you don't know HTML or CSS then I suggest checking out the tutorials on w3schools.com
Some extra stuff can also be found here.