I currently use CMSMadeSimple and as good as they are they're just as bad because they have a horrible support section (forums).Unless this is purely for a mockup that you're gonna show a client, the whole process of using image slices is very outdated. Well it is even for mockups, but it could be useful if you're comfortable with Pixelmator.
However, using images that way to make up a website is bad in lots of ways, to name a few:
- search engines can't parse the content, hence you won't be searchable
- it will scale very bad and look fuzzy if someone zooms or has a retina display
- it takes a lot of time, and is generally just really cumbersome especially if you want to change something.
So, bottomline: don't slice. Use a CMS, like CMS made simple.