I unpacked the little mini-vac. It's small, just a little longer than the average flip cell phone and about as round as a screw driver handle, maybe a little thicker. You can't tell from the picture but it actually includes a small flashlight on it for helping you see in the tight spaces of your keyboard.
It has two attachments, the first is a thin rubber tube (attached to the vacuum in the picture) and one that has a brush on it but also 3 little vacuum tubes to pick up what you move with the brush. I didn't find the rubber tube attachment very useful. It is very flexible and you easily close off the tube when trying to put it between the keys of a laptop, so it can't pick up anything. It's a little better on the desktop keyboard but really I preferred the other attachment.
The little round tubes on the brush attachment mean it won't fit between the keys but that didn't matter. I simply raised one end of my laptop, only an inch or two, and used the brush to move dust and particles from between the keys to the one end. I brushed them either out or to one corner of the keyboard and vacuumed them up. For the desktop keyboard, I actually tipped it upside down. The requisite 'stuff' fell out and I used the brush to go between the keys and bring out anything else. Just vacuumed up the desk and was good to go.
I also found the brush attachment useful for cleaning my monitor. I have an LCD monitor on my laptop, of course, and one for my desktop. I hate when they get all dusty and worse when you get the dust over to one side or a corner but just can't get it off the screen. I used the brush to bring the dust together and the afore-mentioned soft rubber connector to pick it up off the screen, worked perfectly.
I wanted to see how powerful the vacuum was so I put some sprinkles in a bowl, you know those colored candies you get on your ice cream. Picked them up no problem, it's actually more powerful than I thought it would be.
Just be sure that you tip the vacuum up before you turn it off and then go empty it. It collects what you vacuum up just past where the attachments go on and if you leave it tipped down your sprinkles, I mean dust, will fall all over your laptop (luckily I could just vacuum them right back up).
So there you have it, it works, and it's better than just those cans of air alone because where does all that junk go after you blow it out onto your desk?