[quote name='forgot2panic']Whereas Snow Leopard is an incremental, mostly under the hood fine-tuning, Windows 7 is a "back-to-the-drawing-board, we messed up big-time with Vista" overhaul.[/QUOTE]
It's all a matter of perspective. I consider the re-writing of much of Snow Leopard in 64-bit to be a pretty significant change. This is coming from someone who really had no problems at all with Vista; I thought it was decent at launch, and really came into its own with SP1. Win 7, which I'm using right now on both my desktop PC and with Boot Camp on my MacBook Pro, definitely has its improvements over Vista, most notably in lower overall memory usage. However, in my eyes, there's not enough here to justify the high cost of upgrading from Vista, whereas the $25 price for Snow Leopard was well worth it. If MS were to have made the $50 Vista Home Premium to Win 7 Premium upgrade a permanent deal, then that would absolutely be worth it. The current $120 price point is a much harder pill to swallow. The upgrade pricing of other versions is ridiculous. If you want the Windows XP virtual PC mode (also a nice feature), you have to have to have Professional at the least, and that upgrade is $200.
If you think it's worth it, especially if you had bad experiences with Vista, then more power to you.