Philip asked a very good questions in a previous blog entry about the yet to be released "toolset" (he also asked a very good question about DSI which I'll try to address later). He asked, "Will the toolset make it possible to get rid of some ‘expensive install tools' if I don't need their sophisticated user interfaces but want to automate all?" I thought this was a question lots of people might start asking so here's a response "on the main page" (instead of hidden away in a comment).
You always have the option to "get rid of some 'expensive install tools'". I've seen mention of lots of small tools all over the Internet for building MSIs and, of course, you could just build your own tool to call the MSI APIs directly. The real question is what type of support do you need when the tool goes awry or the documentation is found lacking?
Those "expensive install tools" usually come with a 1-800 number (or at least an email address) to contact if you need help. There is usually some sort of contract (implicit or not) that says questions about the "expensive install tools" will be answered by the people you bought the tools from with some degree of promptness. "Less expensive install tools" also usually have an email address that you can send your questions too but there is rarely any guarantee what type of response time you will get or if you will get a response at all. So, if you are willing to spend days tracking down bugs in the "less expensive install tools" or are willing play around with the tool for a couple weeks since the documentation isn't all that clear then "less expensive install tools" may work great for you.
Oh, and those "expensive install tools" usually have some sort of quality assurance process that finds the most egregious bugs before they ever ship their tools. That's because the company's name and reputation is on the line. If they don't maintain a certain quality bar across the tools they release it is unlikely the company will stay in business long. Those "less expensive install tools" are usually written by guys and gals in their free time (i.e. they don't spend a lot of time trying to find all of their bugs) and who have different levels of commitment to maintaining their reputation via a "less expensive install tool" (i.e. if you don't like it, don't use it).
Now, personally, I like to think I have an above average quality bar and a very high commitment bar to projects that I work on. I say "above average quality bar" because bugs and regressions do slip passed me that if I was a bit more careful I would probably catch. However, my very high commitment bar means that when I find a bug later or someone else finds a bug that I missed I work very hard to kill it. Hopefully, this blog entry provides one demonstration and I am sure I will have plenty of other opportunities to demonstrate my commitment to quality when you find bugs in the "toolset".
Now all I need to do is release this "toolset" (just one more meeting with legal, hopefully next week).