1. The iMac is not adjustable, but Apple has designed ergonomically, which is the iMac on the Spacebar for me too high, in order to work comfortably. So if a stylish way seeks to provide its iMac higher can access this regard here. With a 27-inch iMac to me but the overall level was too high and therefore too tiring, if you constantly upside, albeit only slightly, needs to raise upwards.
2. Well, you can push the iMac foot under the Spacebar, thus gaining four USB ports that can be accessed from the front without having to constantly look behind the iMac thereafter. Unfortunately, an iPad 3rd generation will not bring the Spacebar loaded (error message from the iPad) and surely that is something incomprehensible, considering that a) the Spacebar its own power supply and b) the design close to Apple's so obvious.
These two points have led me to send it back and so I give only three stars the Spacebar. The Spacebar bring me neither ergonomically (height) still technically (USB Hub) something and therefore you should make on these two points before buying ideas. For other interested parties can of course be different.
Finally, it should report that the USB ports are white lights and these lights are not switched, is still controlled by the iMac via USB. So you can switch off the computer, then the USB ports continue to shine. If the device is used only for work, then that bothers probably not know who but the iMac used for movies, or the bedroom, this feels possibly disturbing.