Hmm... having read the thread, that does sound like a pretty bad experience, although it seems pretty clear that the problem is with Unsanity's APplication Enhancer framework and not Leopard. It's unfortunate if Apple was initially silent on the problem, but at least they have now posted a comprehensive article explaining how to handle the situation.
I'm not sure if "Blue Screen of Death" is really the best way to refer to the issue - although it does apparently involve crashing and a blue screen, the BSoD nomenclature usually refers to a very specific Windows "feature."
The single-user, command-line solution (described in the linked article) doesn't really take much work. I could see how it could be a bit daunting for experienced users, but since you're a "techno junkie" and you also use Linux, I'm sure it would be no sweat for you.
The "archive and install" option seems to have worked for most users who have tried it as well. "Archive and install" refers only to the operating system, not your entire hard disk, so you will not have to reinstall any programs (although it could potentially affect some settings and configuration files).
I have certainly installed Windows Vista several times (often several times on the same computer, just trying to get one of the installations to actually complete successfully), and installing the whole thing in 30 minutes, even if it worked on the first try, would be quite impressive, and quite rare. The Vista installer also still lags behind the Mac OS installer for unattended setups.
Having Spotlight indexing and/or Time Machine backing up in the background certainly could affect performance, but there is not a single application on my MacBook that is slower under Leopard than under Tiger. In fact, a couple of things are actually much faster. It's surprising that you would have performance problems - what sort of specific issues are you seeing?
The only problems I had with the installation were the minor drive issue described above, and my Keychain wigging out a little after I upgraded (although I admittedly don't use APE). With QuickLook, Time Machine, and enhancements to Spotlight, I don't really see how Leopard could possibly be considered a cosmetic update.
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