@Plusvision - whilst I have complete empathy for your situation having experience something the blank pages initially with one of my sites - there are some huge flaws in your criticisms of WP.
If your business relies entirely on this website then:
1. Why did you upgrade so early as opposed to keeping your install of WP at a version you knew was working - either wait and watch the forums to see what other peoples experiences are or have a second install of wordpress you can use as a sandbox - to play with and test out upgrades before upgrading your mission critical site.
2. If you resent putting time into your website system at the weekends (or evenings or whenever) then is an open source piece of software that inherently requires input from the user into it's up keep, maintenance and troubleshooting really the right solution for you. There are plenty of other options on the market that you could be paying for which provide the type of support you are looking for.
3. WP should provide a repair tool for you??? Read my point number two again - what have you paid WordPress.org to date - I suspect nothing, therefore what do they owe you? The type of support you are looking for in this is what I would expect if I had paid a company for a software solution NOT from an open source project.
4. Did you create a backup of both your database and website before you upgraded? If so, you could reinstall back to your previous installation and all would be fine. If you haven't backed up, why did you install the upgrade?
5. Go back to printed media for promotions - er, no - just don't rely on a system you can't support and manage yourself if it is so critical to your business.
6. Plugins all up to date - by this do you mean simply the latest version or do you mean you checked they were WP 3.1 compatible before upgrading. Even if they were 3.1 compatible you should have them disabled when installing an upgrade and then activate each one individually to check they work properly.
Sorry my friend, it just seems you are lashing out at WP out of frustration and I feel it is a tad unfair.
I sincerely hope you resolve your issue - see my post earlier in this thread for how I resolved the issue on my site. i am also aware for some folks the upgrade seemed to work, then the site vanished later - by changing their permalinks back to default then switching back to their chosen permalink structure also resolved issues.