1.9 I need warranty and security. With commercial software, I can sue if things go wrong.
Don't count on suing. Things go wrong on many MS Windows NT machines every day, and there are no damages awarded by courts. Read your MS Windows license agreement to find out that there is no guarantee whatsoever that ANYTHING will work. Trying to sue would be a waste of your money.
Linux also provides no guarantees, although it is far more secure than any version of MS Windows (assuming comparable functionality is installed on both). If you are really security-sensitive , you can use high-security tools built by companies that rely on the availability of the source code to design and test their security features (e.g., Kryptokom in Germany provides high-security firewalls). The "security in obscurity" implemented in MS Windows has repeatedly been demonstrated to be a naive approach.
"Risk aversion is what dictates you use Linux and other open products, rather than NT. The risks with NT are entirely out of your control, and there is nobody you could sue if anything goes wrong. Why people still believe the myth that Windows in any form offers any bit of accountability "more" than Linux remains a complete riddle to me." (David Kastrup, Research Engineer, Bochum, Germany, "Internet Week," http://www.techweb.com/se/directlink.cgi?INW19990329S0050).
* License