oh, upgrading "works," but if you're a power user or internet junkie your registry and file system is going to be polluted nine ways to tuesday -- especially if you dabble in piracy or are just someone who is constantly installing/uninstalling new software (especially drivers). there's no way an upgrade can solve a bloated, toxic registry.
then again, i take pride in having tremendously slim, small installs and regularly clean the registry, boot/process configs, and file systems. i also have at least three partitions (OS/cache, Data, Games), and perform weekly backups. my computing life is fast, smooth, and stress-free. i only run signed drivers and do complete uninstalls and reg cleans before installing the new ones. my laptops ALL boot in under 10 seconds, i have never blue screened (except when i installed a recent firefox build), and i don't lose data.
it's like owning a motorcycle. if you want it to run well and stress-free, you put a little time into doing things properly.
upgrading? NEVER. upgrading is basically saying "take my existing fucked up environment and slap a largely new one on top of it, busted drivers and busted registry and busted app installations/configurations and all. NO PROBLEM AM I RITE LAWL!"
