Quad vs Duel Core Feelings

I have two computers I've recently built in the last year. Though I read the latest benchmarks and the latest news stories and seen a ton of articles stating that Quad Cores are basically useless in the home environment my own observations have been a little different. Both Computers have a Gateway FPD2275W. Computer 1 is running a Merc Stealth Keyboard and Sidewinder Mouse while Computer 2 has a Logitech Wireless setup.

Computer 1:
Processor: Phenom 9600
Motherboard: GA-790FX-DQ6
Graphics: Radeon 3870
RAM: OCZ 4GB
OS: Vista 64 Home Premium
HD: There is 2. One is a 250 WD and the other is a 500 WD.

Computer 2:
Processor: AMD 64 X2 5400+ 2.8
Motherboard: GA-MA-78G-DS3H
Graphics: Radeon 3870
Ram: Crucial 2GB
OS: XP
HD 680 WD

Since I built the two I have noticed something peculiar. My family naturally gravitates to Computer 1. I have asked them about it and they all state that it just runs better. Not in a big way but that it does. I've noticed this too. Computer 1 seems more responsive, it seems to play Games better, there seems to be less lag, and less restarts. Neither are overclocked nor do I plan to overclock. Overall Computer 1 just seems to run better and has become are most used Computer in the house.
Computer 2 does have it's good points in that it runs the older games that Vista 64 won't but Computer 1 runs the new games better. Is it highly noticiable? Sometimes. Many times I will notice a stutter or lag on Computer 2 while the stutter or lag on Computer 1 is near to zero. When your used to being on a computer that runs smooth those times when your on a computer that doesn't becomes much more noticiable. So saying their is no difference between the Quad and Duel Core for the average family is wrong. At least in our family it is. The Duel Core was less expensive but I feel it was a mistake. There seems to be a big difference between the two.

Another subject is why I went with AMD over Intel? I'll be building a 3rd and 4th computer within the next year and I wanted the ability to be able to swap out parts easily. The 3rd and 4th computer will get the parts from Computer 1 and 2 as I upgrade. AMD makes the process uncomplicated for me. Cost was also a factor.
I do like the Merc Stealth Keyboard and that will be one staying in my buy list for a while. I'm also looking at the Logitech Air Mouse.

I would like to know from others who are in the same situation if they notice the difference like I do? What about the Triple Core vs a Quad and is there a big difference between the two in real life situations like I'm experiencing in my household?