Four out of ten.
Very limited usefulness.
I tried version 4 of this product when I received a free copy on a computer magazine cover disk and I also checked out version 6 which is available on short term evaluation. I'm afraid that I quickly found a number of serious faults with the product which meant that I could not use it at all.
The biggest problem that I have with HoTMetaL Pro is that the product is not really suited for use on a site that already exists! HoTMetaL Pro comes with a built in HTML validator which is uses to check that what you are writing makes sense as HTML.
This is normally a great idea because it will pick up on typos and other mistakes which can be quite tricky to track down when you make a mistake on your page. However, if you load existing code into the program, HoTMetaL Pro will want to carry out the same validation operation on that page.
Now, that might occasionally be useful. Suppose that there is a fault on the page which you didn't spot because the browser that you use to view the site didn't object to the code. (Most browsers make their best guess as to the page author's intent if they spot an error in the HTML syntax.)
However, it is much more likely that something that is odd on an existing page is actually intended to be that way for good reason. I can give a few examples of this.
I am a member of a number of webrings. Different subject areas on my site are in the appropriate rings. When you join a webring, you are given a chunk of html code that you must paste unchanged into your site. The server that runs the webring will then check periodically that the code is showing up on the site. If you change the code, the webring server will see that its code is no longer present and you will be removed from the webring. HoTMetaL Pro didn't like some of the webring code on my site and tried to change it for me.
Also, I use third party a statistics tracking, page counter and ad banner services. I found exactly the same problem with this code as with the webring code fragments. This was worse because of course this code code has to be on every page!
Finally, I have used another page building tool to create some of my pages and this tool has left some HTML tag code on my pages which it uses. HoTMetaL Pro wanted to remove that code as well.
Now, these problems are, for me, complete killers for HoTMetaL Pro. I simply could not even consider using the product on my site. The software does have the ability to turn off validation and so it will leave your existing code unmolested. Unfortunately, if you select this option, the product can only be used in HTML source view. No wysiwyg view is available. In that case, there is little advantage of using this product over a programmer's text editor (such as emacs) which is set up for HTML.
So, for those reasons, I do not use this product apart from the very rare occasions when I want to work on a new page with no stats or webring functions. While it is not bad to use, I must say that if you already have a site, or if you think that, one day your site may expand to use things that will upset HoTMetaL Pro, you should avoid this product.