Agree, Windows XP was sluggish when it was released. Same applies to Win2K though when it first came out compared to WinNT 4.0. 2K was the first Windows to include a shadow effect under the mouse cursor. Oh the extra compute cycles it had to do to render that...
I do agree but don't forget that the difference between NT4 and 2000 was night a day. 2000 wasn't just a reskin of NT4, there were lots of compatibility and usability improvements too. The problem was most people simply couldn't run NT4 outside of an office environment because very few games would run on it, driver support was relatively limited, etc. Windows 2000 was the real bridge between NT office machines and home machines, not XP. Granted consumers wouldn't have seen it that way because most stores didn't sell 2000 on home machines (instead opting for the dumpster fire that was ME) but technology wise XP (original release -- pre-service packs) wasn't a huge advancement from 2000 where as 2000 from NT4 was.