It's only a personal preference. A lot of developers would have both in
their toolbox because the bigger the toolbox the more flexibility you have.
After that, which one works well for you. Dreamweaver does some things that
FP doesnt, such as working with PHP and CFM in addition to ASP or ASP.Net.
FrontPage has some built-in components that make certain tasks easy as they
don't require a lot of custom programming. Basically, whichever one works
best for you is the better program. If you're looking to buy one you may
want to wait a bit as both products will have new versions (in the case of
FP this will be a new product called Expression Web Designer) coming out
within the next 6 months or so.
Hope this helps,
Mark Fitzpatrick
Microsoft MVP - FrontPage