I just started using Sandvox last month. Overall, I really like it. I have the Pro version, which lets me do things like have sections of raw HTML. If you're considering buying it, I highly recommend you watch their intro
screencast and then download a copy to evaluate.
I was accustomed to the free-wheeling world of editing HTML in Kompozer, so at times I feel restricted by Sandvox. I had also tried iWeb, but it was at the other end of the spectrum, making some things (like picture galleries) simple but making me feel like I was trying to build a website with my hands tied behind my back. Sandvox is somewhere in-between, enabling me to build a website quickly and easily, but with some limitations on the style.
I simply adore the one-click publishing. It's so much friendlier than moving files via FTP by hand.