Smaller gives you more options on where she allows you to put it. Who wants a big black tower for a HTPC-Gaming rig? If anyone knows small its the designers of Asus. They are masters at it. It's almost like they are all born with it!
According to the Osedax (Deep Sea Bone-Eating Worm) smaller is better when,
Males don't compete for access to females
Resources are limited
Individuals can't move about
Finding a mate is hard
Under those conditions, it makes sense for males to become small to maximize their mate's success (if they're lucky enough to find one).
How this translates..
E-peen hardly translates in the real world. Why add on that extra pound-age?
No one has money now days. Empty unfilled video card spaces are such a tease!
If it's too big, it's hard to move. This affects over 66% of America's population. Don't let it affect your case too!
Do you really think a potential girlfriend is going to appreciate you dropping your Corsair 900D on her coffee table? No. Get small, get fit. Acquire mates.
Smaller is definitely better if you don't have much desk space. If the build is for an HTPC or you need a portable computer that's not a laptop usually connected to a projector.
I would not want one for a gaming PC but they are great for kids as you can anchor them to a desk.
I don't have much space in my room. That is why small factor is really important for me. I want to build an entertainment system which will be my HTPC, and also a game system. These will be the best for the job.
But really you can be much more imaginative with how your box looks based on the fact that you may want or need it to fit in a smaller space, like on a bookshelf or maybe your car's glove compartment!
It's not a matter of size, but the power and quality behind it.
With ASUS smaller is better because not only do they have the power and quality but the portability and smaller footprint of this hardware makes it ideal.
Smaller is better because it will give me a lot more desk space. It will also be interestine to see how much performance can be done with a small computer!
Smaller is better because I save space on my desk and do not need more then 1 PCI slot. Also, hauling it to a buddies house is much easier It fits under one arm !