Yes... but its not a matter of belief. Vista IS better, its not even really debateable.
Does it require more hardware, yes. Is it significantly different from XP, yes. Are their some features which operate more slowly under Vista than under XP, yes.
However, anyone who has been around computers long enough to remember the transition from DOS, to Win 3.11, to Win NT, to Win 95, Win 98, Win ME, Win 2000, Win XP... etc. understands that not all OS releases are simple little revisions like Win98 or, in this case Vista.
Do you think that all DOS users immediately fell in love with 3.11 for Workgroups? No, they didnt. Or that everyone immediately accepted WinNT & '95 with their slick (for the time) interfaces, hell no they didnt.
People get accustomed to what they use and, unless they're IT types that can just adapt to different OS's... the type that are already used to working in multiple environments.. they're not going to take kindly to change.
I am the IT director for a multi-national corporation and, to whomever the dumbass was that claims Vista is less stable, VISTA IS EASILY 100% MORE STABLE THAN XP.
I manage nearly two hundred systems between desktops and servers, of which twenty three are Vista. While the setup of those systems does take about %30-%50 more time to complete in some cases, once installed I spend less time managing that group of desktops than any other group as a whole. Hell, we have two XP laptops from Sony that give me more grief on then the twenty three Vista machines combined.
Bottom Line: If you buy the hardware to run it, Vista will not let you down. If you try to get by on the cheap, you'll feel it. With Vista, you get what you pay for and the machine has to be built to handle it.